There has been some changes on Amazon’s end that the devs of both integrations are having to deal with.
the latest version of AMP (5.7.11) is working for me and others. I had to jump thru some hoops to get it working again like removing the old integration, restarting HA and then re-adding the integration, the restarting HA few times with a new login for amazon each time. but it’s now working at least for now.
supposedly the latest release of HA (2025.11.1) has a fix for the Alexa Devices integration. I can’t say anything about that one since I usually wait to update to the latest HA version.