SFLUFAN

I'll push another update for this soon, but this is indeed a bug in IPS itself, so hopefully when this is fixed in the next patch for IPS it'll no longer be an issue anywhere 

This error appears to be related to a bug in the current release of IPS. This issue has been reported and should be addressed in an upcoming IPS release, but I have also pushed an application update to the marketplace to provide a temporary workaround for the issue.
However, with it being the holidays, I cannot guarantee when this update will be approved.
I've additionally pushed an update that should allow users migrating from old Advanced Tags and Prefixes installations to still run the migration utility even after upgrading to the latest build of IPS, where ATP can no longer be enabled due to significant compatibility issues.

This should be resolved in the next update, I apologize for the inconvenience!

Looks like it was an issue with the Cloud version, sorry for the confusion. I have fixed this issue on your Cloud community now. This was due to third party add-ons. Please ensure you upgrade all add-ons to be compatible with 4.7.4 and uninstall those who are not.

@SFLUFAN, is this for your self-hosted license as you selected here or is this for your Cloud package? Sorry for any confusion.

Jim...  is the OP self hosted?  He mentioned:
As a result, I was not suggesting that earlier. 😄

If it is just the ACP which is not working, please try the recovery mode. If afterwards it is working, this would indicate a third-party add-on issue.
https://invisioncommunity.com/4guides/client-services/getting-support-r292/#recoverymode