Customer cannot login, the following error can be found in
ERR [panel] Protocol version '126.96.36.199' is not supported. Current protocol version is '188.8.131.52' ]
ERR [panel] Webspace does not exist
Plesk is using Multi-Server.
Management node was upgraded to Plesk 17.5 version.
Service nodes were not upgraded and running under Plesk 17.0
According to Plesk Multi-Server Guide Plesk Multi Server installation should have the identical characteristics:
Use the same operating system.
Use the same Plesk version (to ensure XML API compatibility).
Have the same list of installed Plesk components.
If you install a component, which is local through the management node, it is installed on the management node first. All service nodes are switched to the Unsupported status until you install the component on them.
Upgrade service node to be the same version as the management node.
Sync service node in
Plesk > Nodes > service node > Recheck