At least every second day the server ‘can’t be reached’ with an error message suggesting I check the account settings which comes down to running Diagnostics when the 2 email icons are ‘X’ in red.
The Diagnostics runs briefly and the 2 green ticks reappear suggesting all is good and server connection is renewed and mail begins to flow again.  
Why does this happen so often?
Using version 7.0.26 but also occurred under vers 6 and that’s why I ‘upgraded’ to the Beta 7.