Persistent decline in match rate and eCPM following AdMob outage

[Brandon Jones]

Hi Everyone,

We’ve been facing a significant decline in match rate and eCPM across all our applications on both Android and iOS since the confirmed AdMob outage on December 19, 2024 (incident link - https://ads.google.com/status/publisher/incidents/71zd5GTSJ7xdwPypyyvF).

It’s been several weeks since the incident, but unfortunately, there has been no sign of improvement. We haven’t made any changes to our apps, further confirming that the issue appears to be linked to the outage. The sustained drop has severely impacted our revenue and app performance.

If others are experiencing similar issues or have any advice on how to resolve this, your input would be greatly appreciated. We hope AdMob addresses this problem promptly for everyone affected.

Thank you,
Brandon

[Mobile Ads SDK Forum Advisor]

Hi Brandon,

Thank you for contacting the Mobile Ads SDK support team. 

The issue which was isolated to AdMob traffic only has been fully resolved as of Dec 19, 2024, at 9:30 PM UTC. Ad Requests are now processing normally. Since you are still facing the significant decline in match rate and eCPM across all your applications on both Android and iOS kindly share the below information privately for further investigation:

• app ID
• ad unit ID

You can provide the following details via reply privately to the author option. 

This message is in relation to case "ref:!00D1U01174p.!5004Q02vGrLx:ref" (ADR-00280460)

Thanks,
 

Mobile Ads SDK Team

Feedback
How was our support today?

               

[Brandon Jones]

Hello AdMob Support Team,

We are reaching out regarding the continued fill rate and eCPM anomalies observed across our iOS apps since early December, which worsened notably right after AdMob’s confirmed outage on December 19, 2024. Despite no recent code changes on our end—and particularly no changes on our iOS apps for several months—the fill rate and eCPM have dropped to levels never before experienced. While the standard AdMob recommendations for “optimizing revenue” are appreciated, our data strongly suggests the issue is not simply a matter of yield optimization.

We have four clear points illustrating that the problem likely stems from the AdMob SDK or its backend systems:

1 Stable Performance Until Early December:
Through November 30, 2024, our fill rates were consistently in the high 90% range, with eCPMs between 5.70 USD and 6.40 USD (see table below).
We made no changes to our iOS apps’ code or AdMob integration in this period.

2 Fill Rate Drop on December 3, 2024:
On December 3, our fill rate (match rate + show rate) abruptly plunged from its usual ~99% range to around 90–95%.
This exact pattern (dropping ~5–10 percentage points in fill) is seen across multiple apps, but is especially clear on iOS where we have made zero recent updates.

3 Outage & Drastic eCPM Drop on December 19, 2024:
AdMob had a confirmed outage on December 19, after which the observed eCPM dropped sharply from ~5.50–6.40 USD down to as low as 4.24 USD (or even lower on some days).
Since that day, eCPMs have remained well below historical averages despite no modifications on our side.

4 All Apps Affected, Especially iOS (Unchanged Code Base):
We see the same fill rate + eCPM pattern across all our apps, but iOS data is the clearest “control group” because we have not touched our iOS code or AdMob configuration in months. If it were an app integration issue, we would expect the recent dips to track some change in our code—no such change exists.
Below is an excerpt from our iOS app’s daily AdMob stats (partial columns shown). Notice how the fill rate and eCPM remain steady in November, begin dropping on December 3, and then experience a steep dive on December 19:

Date / Est. Earn. / Observed eCPM / Requests / Match Rate / Impressions   
2024-11-28  195.87       6.26            40635      99.97%       31279         
2024-11-29  189.33       6.19            40395      99.93%       30605         
2024-12-02  162.36       5.61            38026      99.91%       28963         
2024-12-03  157.49       5.33            38686      99.83%       29543         <-- Notice first drop
...
2024-12-18  147.56       5.61            38891      90.79%       28462         
2024-12-19   99.61       4.24            38869      85.89%       27383         <-- Major drop after outage
2024-12-20  144.43       5.29            40064      90.91%       29491         
2024-12-21  137.70       4.97            40346      91.73%       30193         
2024-12-22  119.32       4.71            36741      91.49%       27599         
2024-12-23  123.50       4.71            38611      91.27%       28554         
...
2025-01-06  113.92       4.77            37278      90.48%       27341         

Because:
1 We made no changes to the app,
2 This pattern is consistent across multiple properties,
3 And the changes line up directly with the known AdMob outage and/or potential server-side or SDK-level issues,
we strongly believe the root cause goes beyond simple yield optimization or “normal fluctuations.” We understand eCPM can vary by market conditions, but the data points to an SDK/back-end technical factor.

Request for Investigation
We would greatly appreciate the AdMob Mobile Ads SDK Team’s help in investigating:

* Whether the December 19 outage introduced a technical or server-side issue affecting fill rates and eCPMs, particularly for iOS.
* If any new changes/rollouts in the SDK or ad-serving system took effect around December 3 and December 19 that might have impacted fill/match rate or bidding.
* Whether anything in the AdMob logs could show a mismatch between auctions requested vs. auctions served on iOS.

We are open to sharing additional logs, code snippets, or a more detailed timeline. However, the key point remains: the downward shift began on the AdMob side (with no parallel changes in our apps), and it persists despite standard monetization best practices.

Thank you for your time and assistance, and we look forward to any guidance or insights your team can provide. If there is an internal escalation path for investigating potential SDK or AdMob back-end issues, please let us know how to proceed.

For further clarity, please refer to the attached screenshot and the accompanying CSV file, which contains the full dataset.



Best regards,

Brandon

On Mon, Jan 6, 2025 at 1:07 AM Mobile Ads SDK Forum Advisor <mobile...@forumsupport.google> wrote:

Hi Brandon,

Thank you for providing the requested information.

You may check out Advanced techniques to optimize in-app revenue with Google AdMob guide and optimization tips that can help you regarding revenue optimization. Kindly note that the SDK just requests an ad to the ad server (e.g.: AdMob), and it doesn't have any control over eCPM, fill rate, match rate, or impression of your app. Please note that we can only assist with technical queries/concerns related to the Google Mobile Ads SDK. I'm afraid eCPM, match rate, and impression issues are out of the scope of our team. For revenue-related concerns and the performance of ad units, we recommend that you reach out to the Product Support Team as they're the appropriate team that could help you in this. 

[netl...@gmail.com]

Same here, seems that nobody is paying for ads anymore or something else happened.

[Qais Mrooj]

Do you want to improve payment for ads 300 percent?

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[Mobile Ads SDK Forum Advisor]

Hi Brandon,

The issue which was isolated to AdMob traffic only has been fully resolved as of Dec 19, 2024, at 9:30 PM UTC. Ad Requests are now processing normally.  As stated earlier, for revenue-related concerns and the performance of ad units, we recommend that you reach out to the Product Support Team as they're the appropriate team that could help you in this because we can only assist with technical queries/concerns related to the Google Mobile Ads SDK. I'm afraid eCPM, match rate, and impression issues are out of the scope of our team.

[Brandon Jones]

Thank you for your reply. We’ve already posted our question in the Product Support forum (https://support.google.com/admob/thread/317390497?hl=en&sjid=12446618952103840360-NC) but it appears that group isn’t actively monitored; we’ve received no answer.

Meanwhile, the issue remains:

1 Our app code hasn’t changed.
2 The outage was reportedly “fully resolved” on Dec 19.
3 Yet our fill rate and eCPM are still significantly lower than before.

If our account/backend is fixed and our app code is unchanged, it suggests the SDK may not have fully recovered or adapted post-outage. How can we be sure the SDK isn’t still causing these anomalies, given the clear pattern shift on Dec 19?

We’d appreciate any guidance or escalation you can provide.

Thank you again for your time.

[Brandon Jones]

We’ve also received private messages from other developers reporting the same drop in fill rate and eCPM patterns. This supports our concerns that the issue may be more widespread and not just isolated to our specific apps.
We’ve got three suspects: the app, the backend, and the SDK. The first two have alibis (app not changed, backend reported as fixed) …so guess who’s under suspicion? ;-)

Thanks