Skype for Business Error Move-CsUser : HostedMigration fault: Error=(0), Description=(Pool is in failed over state.). Some info before beginning.

UPN – User Principal Name;

O365domainname – name.onmicrosoft.com;

Servername (on-premise) – name@domain;

Poolname (as an example) – sippoolDB40E11.infra.lync.com.

When migrating users from Skype for Business Online to Skype for Business Server (on-premise) with (as an example) this command:

Move-CsUser -Identity <UPN> -Target <servername> -Credential $cred -HostedMigrationOverrideURL

You can get the next error:

Move-CsUser : HostedMigration fault: Error=(0), Description=(Pool <poolname> is in failed over state.

First of all, check for some users (working and non-working) pool in SfB Online:

#cred = Get-Credential
$session = New-CsOnlineSession -Credential $cred -OverrideAdminDomain "<o365domainname>"
Import-PSSession $session

2. Check users in SfB online with command

Get-CsOnlineUser -Identity "UPN"

3. Check attributes

RegistrarPool and OriginatingServer

If the broken user has another Pool the working user, do next:

P. S. If attributes are the same or the solution not help – create an Office365 support request