Same budgets, same ads, same audiences, and ROAS is still falling. Sometimes it drops overnight, sometimes it slides for weeks. It's one of the most unsettling things to see in Meta Ads Manager, because there's nothing obvious to undo.
Something did change. It just wasn't in your account. It's nearly always one of seven things, and you can usually find which one in about 20 minutes if you check them in the right order.
- First, check whether sales actually fell. Compare Meta's purchases with your store's orders for the same days.
- If only Meta's number fell, it's reporting or tracking. Meta changed how it counts click-through sales in March 2026.
- If store orders fell too, check your site and offer before the ads: stock, prices, shipping and checkout.
- If costs rose but click-through and conversion rates held, it's the auction, and often the season.
- If click-through fell and frequency rose, your ads are worn out.
- Set the last seven days aside. Recent days always look worse than they'll end up.
Seven things that change when you didn't
| What you see | Most likely cause | Check first |
|---|---|---|
| Meta's purchases stepped down in spring 2026; store orders didn't | Meta's attribution change | Blended ROAS, before and after |
| Only the last few days look bad | Attribution lag | The same dates again, a week later |
| Meta's purchases fell suddenly; store orders didn't | A tracking fault | Events Manager, then a test order |
| Store orders fell too, but clicks held up | Your site or offer | Stock, prices, shipping and checkout |
| CPM up; click-through and conversion rate steady | The auction | CPM against the same weeks last year |
| Click-through down, frequency up | Creative fatigue | Frequency and click-through by ad |
| Spend moved to different placements | Automated delivery | Placement breakdown, Advantage+ settings |
1. The report changed, not the sales
Since late March 2026, Meta only counts a sale as click-through if the buyer clicked the ad's link. Sales that followed a like, share, save, comment or profile tap now sit in a separate engage-through category, with a one-day window. Meta announced the change on 3 March 2026 and rolled it out account by account. Billing didn't change. Reported conversions, and so reported ROAS, often did.
If your ROAS stepped down in spring or early summer 2026 and stayed there while store revenue didn't, this is the likely reason. Nothing is broken. Reset your targets against blended ROAS, which is total store revenue divided by total ad spend, and stop comparing this year's platform numbers with last year's. What is a good ROAS for Facebook ads explains blended ROAS and how to set the target.
2. The recent days aren't finished
Ads Manager credits a sale to the day someone clicked or saw the ad, not the day they bought. Someone who clicks on Monday and buys on Friday adds to Monday's numbers, on Friday. So the last few days of any report are always missing sales that haven't happened yet.
If the drop is only in the past week, wait and look again. It often closes on its own. The same lag catches people out after a budget change, which is covered in why Facebook ROAS drops when you increase budget.
3. Tracking broke quietly
A theme update, a new checkout or upsell app, a cookie banner change or a new domain can stop the purchase event firing, or make it fire twice. Ads Manager won't warn you. Purchases just fall, and Meta starts optimizing on less information, which can make real results worse as well.
Open Events Manager and look at the purchase event: how many it received each day, whether both the Pixel and the Conversions API are sending it, and any warnings about duplicates or missing customer information. A falling Event Match Quality score is another sign something changed. Then place a real test order on your phone and check that it arrives once.
4. Something changed on the site
If store orders fell along with Meta's numbers, but clicks and add-to-carts held up, the ads are probably doing their job and the site isn't. Walk the funnel in your store analytics: sessions, add to cart, checkout started, purchase. The step with the drop tells you where to look.
- A bestseller out of stock, or a popular size or color missing.
- A price rise, or a discount that ended.
- Higher shipping costs, or a new minimum order for free shipping.
- A payment method failing, especially on mobile.
- A slower site after a new app or theme update.
- A competitor running a big promotion.
5. The auction got more expensive
Your ads compete with everyone else's for the same people. When more advertisers bid, CPM, the cost of reaching 1,000 people, goes up, and the same results cost more. It's most noticeable in the run-up to Black Friday and Christmas, and around big events in your market. If CPM rose while click-through and conversion rates held steady, it's the auction, not your ads.
You can't fix the auction, but you can plan for it. Expect lower ROAS in peak weeks, lean on warm audiences and email, which convert better when cold traffic gets expensive, and judge the season against the same weeks last year rather than last month.
6. Your ads wore out
Most accounts lean on one or two ads. Over the weeks, the same people see them again and again. Frequency climbs, click-through falls, and costs follow. Nothing in the account changed, but the audience's patience did.
Check frequency and click-through for your top ads over the past 30 to 60 days. If the leading ad is fading and nothing new is ready to take over, the whole account drops at once. The fix is a steady supply of new creative. On one climbing gym we manage, we tested 118 creatives across 34 campaigns in ten months, on daily budgets between £5 and £15. Our guide to ecommerce creative testing shows how to keep that going without burning budget.
7. Meta changed where your ads run
Advantage+ placements and creative enhancements let Meta choose where your ads appear and adjust how they look, and that delivery can shift over time without anyone editing the campaign. Break your results down by placement for the weeks before and after the drop. If spend moved toward placements that convert poorly for you, that's your answer. Check the creative enhancement settings on your top ads too, so you know what people are actually seeing.
The 20-minute diagnosis
Line up Meta with your store
Pull the last 60 days by day: Meta's purchases and purchase value next to your store's orders and revenue. If the store is steady, sales didn't drop, the measurement did, so go to step 2. If both fell, skip to step 4.
Set the last seven days aside
Compare periods that ended at least a week ago, so attribution lag isn't part of the picture.
Check tracking and attribution
In Events Manager, check daily purchase events, whether the Pixel and the Conversions API are both sending, and any warnings. Place a test order. If the step down lines up with spring 2026, allow for Meta's attribution change.
Walk the store funnel
Sessions, add to cart, checkout started, purchase. Find the step that fell, then check stock, prices, shipping and payment on a phone.
Check the auction
Compare CPM with last month and with the same weeks last year. Rising CPM with steady click-through and conversion rates means market pressure, not a broken account.
Check the creative
Look at frequency and click-through for your top ads over 30 to 60 days. A fading top ad with nothing new behind it is fatigue.
Check delivery
Break results down by placement before and after the drop, and review the Advantage+ creative settings on your top ads.
What not to do
- Pausing your best campaigns. Restarting them later means relearning from scratch.
- Doubling the budget to make up the difference. That usually lowers ROAS further.
- Rebuilding the account. Big edits reset the learning phase and add a second problem to the first.
- Judging on two or three days of data.
- Switching attribution settings mid-diagnosis, so you're no longer comparing like with like.
When it's worth a second pair of eyes
If you've worked through the list and can't find the cause, or you've found it and can't fix it, that's when outside help pays for itself. Tracking faults and a steady supply of creative are most of what we fix in Meta ads management for ecommerce brands. For an ongoing routine, our weekly Facebook ads health check catches most of these before they cost you a month.
Questions people ask
Why is my ROAS lower in the last few days?
Because Meta credits each sale to the day of the ad, not the day of the purchase, and a sale can be credited up to seven days after a click. The most recent days are always missing sales that haven't happened yet. Judge any period at least seven days after it ends.
Did Meta change how it counts conversions in 2026?
Yes. From late March 2026, click-through attribution counts only clicks on the ad's link. Sales that followed likes, shares, saves or comments moved to a separate engage-through category with a one-day window. Billing didn't change, but reported ROAS often fell.
Can Meta tracking break without me changing anything?
Yes. Theme updates, new apps, cookie banner changes and platform updates can stop the purchase event firing, or make it fire twice. Check Events Manager and place a test order after any change to your site.
Should I pause my ads when ROAS drops?
Not straight away. Find the cause first. Pausing and restarting throws away what campaigns have learned, and if the drop is attribution lag or a reporting change, you'll have switched off ads that were working.
How long should I wait before reacting?
At least seven days after the end of the period you're judging, so the attribution window has filled in. Act sooner only if tracking is clearly broken or the site has a fault.
What ROAS should I compare against?
Your break-even ROAS, worked out from your margin, and measured on blended numbers: total store revenue divided by total ad spend. Platform ROAS is useful for comparing campaigns with each other, less so for judging the whole business.
When is it worth getting help?
When you've ruled out reporting, tracking and the site, and the drop has lasted more than a couple of weeks. We're not the right fit if your store hasn't yet proven it can sell without ads. Fix the offer first.
Still can't see why the number fell? Book a strategy call and we'll go through the account with you and find which of the seven it is.
