It's working now for me (June 8, 2022) with no changes on my end.

I'm also having the same problem and getting the exact same error message today (June 7, 2022). It was working a few days ago, but it doesn't work now. I'm using a Windows 10 machine with Java 1.8.

Oh by the way, is your bug report public ? if so do you have a link to your bug report? I posted the bug report number in my previous post, but I don't think you can see anyone's bug reports except your own.

This issue is extremely annoying, there is also very little to be found on google/bing and etc If anyone can shed a bit of light on the matter that would be fantastic. The bug report I filed has a resolution status of "Potential fix identified - For a future OS update". Hopefully, this means that they have found the cause of the issue and will fix it soon.

if you set from .reliable to .unreliable the warning goes away, so it indeed has smth to do with packets not being able to send at first but then it will. Its annoying and I can't find any method to silence this warning I'm only using unreliable, and I still get the error every ~11 seconds, even when no packets are being sent by my app. I tried switching to reliable, and in addition to getting the error every ~11 seconds, I get the error every time my app sends a packet. This occurred when testing on an iOS 13.5.1 device. When testing on an iOS 12.4.6 device, I didn't see this error in the debug log.

I filed a bug (FB 7829889).

During a Game Center real-time match, I'm seeing this error approximately every 11 seconds: 2020-06-28 10:09:37.425385-0700 <app name>[12860:1962955] [ViceroyTrace] [ERROR] AGPSessionRecvFrom:1954 0x123f87740 sack: SEARCH FAILURE SERIAL NUMBER (00000000) FROM (54D07057)... I think this could be due to an aggressive connectivity check. Eventually, with a weak internet connection, this causes the real-time match to disconnect. In the past 3-4 weeks, some users have been reporting that 70-80% of their real-time matches have been getting disconnected. I reported a bug (FB 7816074).

You can if you put the tag in square brackets. See dev forum search info here - https://developer.apple.com/support/forums/.

For me, both places link to the same place (without a +) and resolve correctly.

According to this post - https://developer.apple.com/forums/thread/650314, they have enough bug reports for it already.

It's fixed now for me. Just now, I was able to go into "Agreements, Tax, and Banking" and accept the agreement.

Thank you for reporting this issue. This error often indicates the Program License Agreement has not been agreed to on the developer website. Please ask the Account Holder to review the latest agreement at: https://developer.apple.com/account. If this has already been agreed to or no alert is shown on that page, please let us know. I'm the account holder. I went to the site you noted (https://developer.apple.com/account), reviewed and agreed to the agreement in the banner at the top, but the message noted in the OP is still appearing at the top of App Store Connect for me.

I posted - https://developer.apple.com/forums/thread/649731 about this yesterday, and it was suggested that I file a bug report/suggestion, which I did.

Is there a way to post a feedback/bug report number without it getting edited out with asterisks? (as in my previous post)

You should definitely file your own bug about that. I submitted a bug/suggestion (FB*******) for the sort order.