Eventual time out of session (suspected)

Hi All

While running a script I do a connection to SkypeOnline so I can set some policies on potentially thousands of students in a tenant:

Import-Module SkypeOnlineConnector
    $SfBsession = New-CsOnlineSession -Credential $cred -Verbose -OverrideAdminDomain $MSDomain
    Import-PSSession -Session $SfBsession

After a while of running the loop successfully setting policies, it starts throwing this:

The fact that if you kick it off again it runs for ages says to me it is timing out of the imported PS Session so how do I work around this?  Can I check for session expiry or can I just re-authenticate every 10 minutes, pull in another session and then continue the user list?

The loop is just this:

$ALLUsers = Get-MsolUser -All | ?{ $_.isLicensed -eq "TRUE" }
$ALLUsersApply = $ALLUsers | ?{ ($_.Licenses | ?{ $_.AccountSkuId -eq $LicenseSelection}).Length -gt 0} | select SignInName
foreach ($User in $ALLUsersApply) {
    write-host "Grant-CsTeamsMessagingPolicy -PolicyName $PolicySelection -Identity " $User.SignInName
    Grant-CsTeamsMessagingPolicy -PolicyName $PolicySelection -Identity $User.SignInName
    write-host "Grant-CsTeamsMeetingPolicy -PolicyName $PolicySelection -Identity " $User.SignInName
    Grant-CsTeamsMeetingPolicy -PolicyName $PolicySelection -Identity $User.SignInName
       }

Thanks.