Here's one possible issue: Can't login to FMS database on new Mac, other Macs can
This is one of many acknowledged bugs that can be found in the Known Bug List thread here in the Report an Issue section of the forum.
It can also be downloaded as a database file from: https://www.dropbox.com/s/jt09b82i0xijbu3/FMP%20Bugs.zip
Thank you so much Phil. i waorked on this for 2 days.
There was no server.pem in the MacBook FMP app, so I copied the one on my iMac & it now works great! Thank's again for a speedy fix.