Unable to access network drive on microsoft's cloud server

For the past couple of weeks, 2 of our users have been unable to access our clients network drive on the Microsoft azure server. This is an intermittent problem as sometimes it works and sometimes it doesn't. All other users can access this drive fine except those two.

• I have uninstalled and installed their Microsoft client for networks.
• I have adjusted the power management feature for Microsoft client for networks.

• I have adjusted their permissions to give them full control to this network drive.

• The only thing that works is wiping out the saved credentials under credential manager and rebooting their machines.

Any thoughts on what might be causing this?

Thanks