If the customer migrated their BizTalk server from perhaps 2010 to BTS 2013 R2. The followed all the steps to change the environment details in https://assist.biztalk360.com/support/solutions/articles/1000220664. But this is not a simple Environment server name change or Database name change.
You know that if you are monitoring BizTalk server, that exact server versions Admin console component must be installed on the BT360 server.
In this case, the customer forgot to upgrade the BizTalk360 server while migrating the BizTalk server to a higher version.
Once the Admin components were upgraded as well, all the issues were resolved.