Azure partition refresh issue

Hi all,
I am refreshing ds partitions via Azur runbooks and powershell scripts. This week I noticed that the error below appears (previously everything worked fine)

This is the line that its calling:

$Srv.Connect($connectionString)

And the connection string:

$connectionString ="Provider=MSOLAP;Data Source=$XmlaEndpoint;User ID=app:$PowerBIServiceApplicationID;Password=$PowerBIServiceApplicationKey;Persist Security Info=True;Impersonation Level=Impersonate"

Do you have any suggestions why suddenly this script stoped working a week ago?

Thanks in advance!