11 min. read

We mostly talk about online commerce as a front-end game. Better photos, faster checkout, conversions, targeted ads…

In 2026, that’s the “easy part”.

Most e-commerce failures don’t look like failures anymore. The site converts. The campaigns perform. The dashboard is green. And yet margins bleed, customers churn, and ops teams spend their days patching holes with manual fixes.

Modern commerce, especially hybrid commerce or omnichannel commerce, usually breaks in the gaps. It’s when the store says one thing, inventory says another, fulfillment can’t keep up, returns go to chaos, and a “simple” tech stack turns into systems that don’t agree with each other.

This list is about e-commerce mistakes your marketing gurus don’t cover enough.

1. Treating inventory as “close enough” across channels

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This one is the number one risk in hybrid commerce for a reason. When online and in-store shoppers pull from the same stock, inventory must be accurate in real-time. Otherwise, you can end up “selling the same product twice.” 

McKinsey shares a case where a retailer built a single view of inventory across stores and warehouses. That change helped double conversion rates. 

What the mistake looks like is simple. The product page says “in stock.” The store cannot find it. The warehouse count is off by a little. The result is substitutions, delays, or cancellations. 

Customers read that as “I cannot trust your delivery promise.”

A simple fix we suggest to our clients:

  • Define one “available to promise” number based on real availability, not raw stock on hand.
  • Use reservation rules for BOPIS and ship from store, including hold times and release rules.
  • Track oversells, cancellations, and substitutions weekly. Treat them as inventory accuracy metrics.

If your systems are split across POS, ecommerce, OMS, WMS, and a 3PL, this is often worth bringing in an OMS or inventory specialist. Getting the logic right pays back quickly.

2. Promising fast delivery without building reliability

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McKinsey found that parcel delivery speed has accelerated by about 40 percent since 2020, dropping from 6.6 days to 4.2 days by mid-2023. Expectations moved with it. Faster delivery is now normal, which makes late or missed deliveries feel even worse.

In Europe, delivery networks are also shifting because reliability and cost matter. The Financial Times reported a rapid expansion of parcel lockers across Europe as carriers and consumers push for cheaper, more convenient delivery and pickup options. 

To illustrate what it looks like in practice: A brand promises next-day or tight delivery windows on every order, even when it cannot control carrier capacity, address quality, handoffs, or peak season. The result is more late deliveries and more refunds.

A simple fix:

  • Promise what you can deliver consistently. Use realistic cutoffs and delivery windows by region and by season.
  • Offer a reliable alternative at checkout, like pickup points or lockers where they exist. Many customers choose certainty over speed.
  • Treat delivery issues as a measurable quality problem. Track late deliveries, failed attempts, and support tickets, then fix the biggest drivers first.

If delivery performance depends on several partners, this is worth assigning clear ownership within your team. Someone needs to be responsible for the end result, not just the shipping label.

3. Running disconnected systems and calling it omnichannel

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When systems do not talk to each other, the cost shows up in places leaders hate. Shipping costs go up, support tickets pile up, and “simple” orders turn into split shipments.

One example from a Fluent Commerce report puts a number on it. If your split shipment rate rises to 1.8, the report shows your average shipping cost per order can almost double. 

This is exactly what distributed order management is meant to prevent. It is a software that optimizes fulfillment using inventory across the network to hit service levels like fill rate and on-time delivery, while staying cost-effective. 

What the mistake looks like is simple. Your store system, ecommerce platform, warehouse tools, and finance records each have a different version of reality. The customer places one order, but internally it creates a series of manual fixes.

A simple fix:

  • Pick one system to “decide the truth” for orders and inventory availability, then make the others follow it.
  • Use clear routing rules so orders go to the best location, not the most convenient one at the moment.
  • Track a few signals weekly. Split shipments, cancellations due to stock, late refunds, and where is my order contacts.

If this is already messy, do not try to fix it with spreadsheets and Slack. Bring in someone who has implemented unified order and inventory logic before. A short, focused project often beats months of patchwork.

4. Launching ‘ship from store’ without store-ready ops

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Services like buy online, pick up in store can lower fulfillment and logistics costs and bring extra store traffic. That upside is real, which is why so many brands push it fast.

The problem is what happens when stores are not set up to fulfill orders like a small warehouse. 

An HBR case on ‘buy online, pickup in store’ describes the common failure pattern. Store teams get a bigger workload, struggle to keep up with fulfillment demands, and customer satisfaction drops. 

What the mistake looks like is simple. 

Online orders start landing in stores. Store employees are asked to pick online orders while still handling their normal in-store duties. Items are hard to find, or already sold, or misplaced, pickups are late, and then customers show up and wait, or get cancellations. 

You lose trust, and you also lose money through rework and support time. A few simple fixes here:

  • Give stores a clear “how we fulfill” playbook. Who picks, where orders are staged, and what the pickup handoff looks like.
  • Set realistic promises. Only offer fast pickup when the store can meet it consistently.
  • Start with a small rollout. Prove it in a few stores, then expand once your process is stable.

If your online shop and store systems do not share the same view of stock and reservations, it is often worth bringing in someone who has implemented this before. The fastest route is usually not more effort from the store team. It is better rules and better system setup.

5. Treating returns as a policy instead of an operation

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McKinsey estimates that in categories like apparel, 15% to 30% of all online orders are returned, and poor return handling directly increases costs while lowering repeat purchase rates. 

We’ve seen how rising return volumes quietly eroded margins for European retailers. Especially as free returns became the norm without the operational backbone to support them. 

Customers feel this immediately. Slow refunds reduce trust. Confusing return steps increase support tickets. Over time, shoppers simply stop coming back.

A simple fix:

  • Design returns as a real flow, not just a policy page. Decide where items go, how fast refunds happen, and what gets resold or written off.
  • Reduce avoidable returns by improving product information like sizing, photos, and descriptions.
  • Measure return reasons and costs regularly, then fix the top drivers first.

If returns are spread across warehouses, stores, and partners, this often needs dedicated ownership. When no one owns returns end to end, they quietly become one of the most expensive parts of the business.

6. Treating digital accessibility as an edge case

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As of June 2025, accessibility is no longer optional for e-commerce businesses selling into the EU. The European Accessibility Act (EAA) is now in effect and requires digital services, including e-commerce websites and checkout flows, to meet defined accessibility standards. 

This is not a small audience issue. The European Commission estimates that over 87 million people in the EU live with some form of disability, and many more benefit from accessible design due to temporary impairments, aging, or situational constraints. 

This is not just a legal risk. Studies consistently show that accessibility improvements improve usability for everyone, especially on mobile, where clarity, contrast, and simpler flows reduce friction and abandonment.

A simple fix:

  • Review your site against basic accessibility standards, especially navigation, forms, and checkout.
  • Fix high-impact issues first. Clear labels, readable contrast, keyboard navigation, and understandable error messages go a long way.
  • Build accessibility into design and development going forward, instead of retrofitting it after launch.

If accessibility has never been part of your product or design process, this is a good moment to involve specialists. It is usually faster and cheaper to fix this intentionally than to react after customers or regulators force the issue.

7. Treating vendor cybersecurity as “someone else’s problem.”

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This risk is not theoretical anymore. Verizon’s 2024 DBIR found that 15% of breaches involved a third party, including software vulnerabilities and other supply chain issues. 

NIS2 directive pushes in the same direction. It expects covered organisations to address supply chain security, including security-related aspects of relationships with direct suppliers and service providers. We also call out this exact requirement when discussing NIS2 compliance measures for supply chains. 

What the mistake looks like is simple. A business tightens its own security, then assumes partners are fine. 

The issue is that commerce runs on partners. Payment providers, marketing tools, plugins, agencies, logistics providers, and customer support platforms often have deep access. That is why supply chain attacks keep working. Attackers look for the easiest route in, not the most direct one.

A practical way to think about it is to identify your “must not lose” systems and data first. We call these your cybersecurity crown jewels. If a vendor is related to those, that vendor is not low risk.

A simple fix:

  • Make a short list of critical vendors. Focus on the ones that touch payments, customer data, storefront uptime, and order operations.
  • Set minimum security expectations and incident reporting rules in writing. NIS2 makes this a serious governance topic, not a nice-to-have. For a plain language overview, check what NIS2 means and what to do now, and this simple NIS2 compliance guide.
  • Reduce access. Give vendors only what they need, review access regularly, and remove it when it is no longer needed.

If this feels like a lot, that is normal. Vendor risk is a capability. Many teams move faster by bringing in specialists to set up a vendor security baseline and a repeatable review process.

8. Letting product data rot, then blaming marketing

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Bad product data does not just hurt conversion. It breaks trust.

In our overview on PIM systems for e-commerce, we show how 86% of consumers are unlikely to buy from a brand again after an experience with inaccurate product information. 

What the mistake looks like is simple. Variants are messy. Attributes are missing. Size info changes between pages. Images do not match the selected option. Category structure is inconsistent. 

Then returns go up, SEO gets weaker, customers buy the wrong thing, and warehouse picking gets harder because SKUs and labels do not line up cleanly.

This is why the teams that treat product data as “content” usually end up paying for it in operations. The product page is the start of the supply chain, not just a marketing asset.

A simple fix:

  • Assign a clear owner for product data, not “everyone.” One person or function owns accuracy, completeness, and updates.
  • Standardize the basics for every product. Titles, variants, dimensions, materials, compatibility, size guidance, and updated images.
  • Add validation rules so bad data cannot go live. Missing attributes, duplicate variants, mismatched images, or inconsistent sizing should be blocked, not published.
  • Sync catalog rules with fulfillment reality. If the warehouse and customer see different product definitions, errors will keep happening.

If your catalog is large or spread across several tools and markets, it often helps to bring in a product data specialist to set up the standards and validation once, then your team can run it day to day.

Mistakes need an expert eye

Most e-commerce mistakes in 2025 do not look like mistakes. They look like normal operations until the costs stack up and customers start losing trust.

If you fix the seams first, inventory truth, fulfillment reliability, returns, product data, and vendor risk, growth becomes easier because you stop fighting your own system.

If you want a second opinion on where you are leaking money or trust, you can book a free call with one of our experts. We will help you spot the highest impact fixes and what to tackle first.

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