Quick Answer: When you add a Target CPA below what your conversions actually cost, or on a campaign with little conversion history, smart bidding loses confidence it can hit the number and quietly stops entering auctions. Impressions dry up and the campaign shows "Limited by budget" even though budget was never the problem. To restart delivery, raise the target to 1.5x or 2x your real 30-day CPA, or remove the target and run plain Max Conversions. Then leave the campaign alone for a week.
The Freeze Always Looks the Same
An advertiser running a local service campaign has around 10 conversions for the month. Cost per conversion feels high, so they add a tCPA a little under their current number. Seems reasonable. The next morning, impressions are near zero. Spend is gone. Four days later, still nothing.
Another advertiser sets a Target CPA on a campaign with no recorded conversions at all. Delivery dies within hours. They remove the target. The campaign stays frozen anyway, now wearing a "Limited by budget" label it never had before.
Both end up in the same place. Afraid to change anything else, afraid to do nothing, and dreading the client call where they have to explain why a working campaign went dark.
"Limited by Budget" Is Not About Your Budget
This label is the most misleading part of the whole episode. It reads like Google wants more money. What it usually means after a bid strategy change is that the algorithm has throttled delivery because it can't predict conversions at the target you gave it.
Two things make it worse. First, the label is sticky. It reflects recent history, and it hangs around for roughly five days of spend staying under your daily cap before it drops off. Second, removing the tCPA doesn't snap delivery back. The system waits for the account to look stable again before it ramps up. So you can revert everything and still see nothing for a day or two. That silence is normal, not proof you broke it worse.
Why the Algorithm Went Quiet
Smart bidding is a prediction engine. It enters an auction when it believes the click can convert somewhere near your target. That belief comes entirely from conversion data inside your ad account.
Give it a target below your realized CPA and you've told it to hit a number it has never once achieved. Give it no conversion history and you've told it to optimize toward an event it has never seen. In both cases it does the same thing. It protects your money by barely bidding at all.
And because every bid strategy change restarts the learning phase, each panicked toggle extends the outage. The advertisers who thrash between tCPA, Max Conversions, and manual CPC in a single week keep resetting the clock they're waiting on.
Here's the recovery sequence.
Step 1: Count Your Conversions Before Anything Else
Open the campaign and check conversions for the last 30 days. The working rule of thumb is 30 conversions in 30 days, recorded inside Google Ads, before a tCPA makes sense. GA4 events that were never imported don't count. Leads sitting in your CRM don't count. If you're under the threshold, tCPA was the wrong tool for this campaign stage, and the fix is a different bid strategy, not a better target.
Step 2: Raise the Target or Remove It
If you have real volume, reset the tCPA to 1.5x or 2x your actual 30-day CPA. That feels like surrender. It isn't. A target is a ceiling, not a goal, and a generous ceiling gets the campaign bidding again while efficiency recovers. If you're under 30 conversions, remove the target entirely and run Max Conversions, or drop to manual CPC or Max Clicks and rebuild conversion history first.
Step 3: Don't Touch It for Seven Days
Hover over the campaign status. If it shows a learning note, the clock is running. Every edit to bidding restarts it. Set a calendar reminder for a week out and stay out of the bid settings until then. Daily impressions returning is the first signal, usually within one to three days.
Step 4: Exclude the Frozen Days
Use data exclusions to block off the dates when the campaign was stalled and you were changing settings. This stops the algorithm from treating that dead window as a lesson about your account.
Step 5: Tighten the Target Slowly
Once volume is stable, lower the tCPA 5 to 10 percent at a time, waiting 7 to 10 days between cuts. The moment impressions sag after a cut, go back a step. That's your account's real floor for now.
If the deeper issue is that your real conversions happen after the click, a booked job, a quoted call, a signed contract, then Google never sees the outcomes that matter and every bid strategy is guessing. That's an offline conversion tracking problem, not a bidding problem. The free OCT Setup Checklist walks through getting those CRM conversions back into Google Ads so smart bidding finally has real data to learn from. Grab it at freak.marketing/oct-checklist.
FAQ
How long until the "Limited by budget" label goes away?
Plan on about five days. The label looks back at recent history, so it needs several consecutive days of spend staying under your daily budget before it clears. If delivery has recovered, ignore the label while you wait it out.
Should I raise the tCPA or switch back to Max Conversions?
Both restart delivery. Raising the target is the softer move because you keep the same bid strategy and lose less learning. Switching strategies is a harder reset that can take longer to ramp. If the campaign has healthy conversion volume, raise the target. If it never had volume, switch.
Do GA4 or CRM conversions count toward the 30-conversion threshold?
No. Smart bidding only learns from conversions recorded in the ad account. GA4 goals must be imported, and CRM outcomes need offline conversion tracking with a GCLID or enhanced conversions for leads to make it back into Google Ads.
Can my Target CPA be higher than my daily budget?
Yes, and sometimes it should be. But do the math first. If your CPA target is $80 and your daily budget is $30, you can only afford a conversion every few days, which is too little data for the algorithm to learn from. Either the budget or the expectation has to move.