Solved: Can't Create Facebook Lookalike Due to Purchase Event

Hi there,

Thanks for reaching out!

I had a look at the issue you're facing with your Meta lookalike audience, and honestly, it's a very common problem, especially over the last couple of years. It can be incredibly frustrating when the platform gives you an error that doesn't seem to match your own data.

The good news is that this is entirely fixable. The error message about not having enough people is actually a symptom of a deeper, more important issue: a breakdown in your data and tracking. Once we sort that out, not only will this specific problem disappear, but your entire advertising account will become more powerful and profitable. Let's get this sorted for you.

We'll need to look at your data foundation... because that's the real problem

Right, let's get straight to it. The error message Meta is showing you is technically correct, but it's misleading. The platform isn't broken; your data feed to it is. When it says it has only received 66 purchase events, it's telling you the truth from its perspective. The real question is, where did the other 734 orders go?

The culprit is almost certainly the big shift in data privacy that started with Apple's iOS14 update and App Tracking Transparency (ATT). In the past, the Meta Pixel—a piece of code on your website—could happily track most users as they browsed your store. But now, many users (especially on Apple devices) can and do block this kind of tracking. This means the Pixel, on its own, is now half-blind. It's missing a huge chunk of data, which is exactly what you're seeing with your numbers.

The solution, and this is non-negotiable for any serious advertiser today, is to implement the Conversions API (CAPI).

Think of it this way:

• The Pixel (Browser-Side Tracking): This is like a security guard standing at the front door of your shop, trying to count people as they come in. If someone wears a disguise (like an ad blocker or privacy setting), the guard can't see or count them properly.
• CAPI (Server-Side Tracking): This is like your point-of-sale system inside the shop. It doesn't care what disguise someone is wearing; if a transaction happens, it's recorded directly in your server's records. CAPI then sends this reliable, confirmed transaction data directly from your server to Meta's server, completely bypassing the user's browser and its privacy blockers.

By using both the Pixel and CAPI together, you get the best of both worlds. The Pixel catches what it can, and CAPI fills in the gaps with high-quality, reliable data. This process is called 'deduplication', and Meta handles it automatically to ensure you don't double-count events. For an eCommerce store, setting up CAPI is often straightforward through platforms like Shopify, which have native integrations.

Getting this right is the single most important thing you can do for your ad account. Without accurate data, Meta's algorithm can't learn who your best customers are, it can't optimise your ad delivery properly, and you can't build powerful audiences like the purchase lookalike you're after. You're essentially flying blind and leaving a huge amount of money on the table.

I'd say you need a proper audience strategy, not just one lookalike...

Once your tracking is solid, we can talk about audiences. Your instinct to create a lookalike from your purchasers is a good one. It's often the highest-quality cold audience you can build. But stopping there is a common mistake. A robust advertising strategy doesn't rely on a single audience; it uses a tiered structure that speaks to potential customers at every stage of their journey.

I organise this using a simple Top-of-Funnel (ToFu), Middle-of-Funnel (MoFu), and Bottom-of-Funnel (BoFu) structure. The idea is to prioritise audiences that are closest to making a purchase, as they will almost always give you the best return.

Here’s how I would typically prioritise audiences for an eCommerce account. You should test these in order, starting from the bottom (BoFu) and working your way up as you gather more data and increase your budget.

Your immediate workaround: While you're getting CAPI setup and collecting more accurate purchase data, don't just sit and wait. Go into your Audiences tab and create a lookalike from the next-best event. Do you have at least 100 'Add to Cart' or 'Initiate Checkout' events from a single country? Probably. Use that as your source for now. It won't be quite as potent as a Purchase lookalike, but it will be a thousand times better than not running any prospecting ads at all. You can also export a list of your 800 customers from your eCommerce platform and upload it directly to Meta to use as a source. This is another excellent way to bypass a faulty pixel.

You probably should calculate what you can afford to pay for a customer...

A common question I get is "what's a good cost per purchase?". The truth is, it depends entirely on your business. A "good" CPA for a business selling £500 items would be a disaster for one selling £25 items. Instead of chasing a low CPA, you should focus on your Return On Ad Spend (ROAS). The real question you should be asking is: "How much can I afford to spend to acquire a customer and still be profitable?"

To figure this out, you need to know two things: your Average Order Value (AOV) and your break-even point. For example, if your average order is worth £100 and your profit margin on that order is 60% (meaning £60 is gross profit), your break-even CPA is £60. Any cost per purchase below that is profitable.

A healthy target for many eCommerce businesses is a 3x ROAS, meaning for every £1 you spend on ads, you get £3 back in revenue. To hit a 3x ROAS on a £100 AOV, your maximum affordable CPA would be £33.33 (£100 / 3). Knowing this number is powerful. It stops you from panicking and turning off an ad set with a £25 CPA, because you know it's still very profitable. It also tells you when to kill an ad set that's hitting a £70 CPA.

I've built a simple calculator for you below. Play around with the sliders for your AOV and your target ROAS to see what your maximum CPA should be. This will give you a clear target to aim for when you're optimising your campaigns.

You'll need to stop selling products, and start selling solutions

Even with perfect tracking and the best audiences in the world, your ads will fail if your message is wrong. Too many businesses just list features. "Handcrafted silver necklace." "100% cotton t-shirt." This doesn't work because it doesn't connect with the customer's real desires.

You need to sell the transformation, not the product. A great framework for this is the Before-After-Bridge.

• Before: Describe the customer's world without your product. What is their problem or frustration? Make them feel understood.
• After: Paint a picture of their world with your product. What is the ideal outcome? How do they feel?
• Bridge: Position your product as the simple, obvious bridge to get them from the 'Before' state to the 'After' state.

This approach shifts the focus from what your product is to what your product does for the customer on an emotional level. This is what stops the scroll and gets people to actually click on your ads. This is what gets results.

I've detailed my main recommendations for you below in a table to give you a clear path forward. This is the exact process we'd follow to get your account not only working, but performing at a high level.

As you can see, fixing a single audience error opens the door to a much more professional and effective way of advertising. It moves you from just 'running ads' to building a predictable system for growth. While the principles are straightforward, the execution, especially the technical setup of CAPI and the continuous testing and optimising required, can be time-consuming and complex.

This is where working with an expert can make a huge difference. We handle this entire process for our clients, from the deep technical setup to strategic planning and creative testing, ensuring every part of the machine is working perfectly to grow their business.

If you'd like to have a chat and walk through your ad account together, we offer a completely free, no-obligation initial consultation. We can take a look at your specific setup and give you some more tailored advice on how to achieve your goals.

Regards,

Team @ Lukas Holschuh