Teams randomly locking accounts and collaboration issues with another school

Hi,

I'm the IT manager at a school we have just started using teams but we have come across a few issues.

1. Randomly teams will lock users out of their accounts and myself as the admin has to reset the passwords so they can get back in.

2. A few members of staff have been invited to collaborate with another school but when we follow the links it asks to create them accounts even though they have accounts already and when they try to create them it asks them to contact the Admin to do it for them, but I have checked the settings in Azure and they should be able to accept the invites.

The issues could be caused with Azure as I get emails telling me the identity synchronization from on-premises is unhealthy.

Azure does Sync but we have a .local domain, we use a school domain (schoolname.co.uk) for emails and office 365 uses the username@schoolname.onmicrosoft.com

could Azure be causing the issues we are having?

thanks

Michael