When using a GMSA account for the SQL connection when upgrading from 7.3 to 7.5, you may encounter an error "Could not connect to the SQL server" (4379792)

When performing an upgrade from 7.3 to 7.5 on the database connection wizard, you may encounter an error "Could not connect to the SQL server":

This is due to being unable to impersonate the GMSA account as local system is recorded in advanced debug logging. Impersonation was broken in 7.3 and was not fixed until later versions of 7.4 and above.

SOLUTION 1:

Use a regular domain account until the upgrade to 7.5 has been completed then switch back to a GMSA account.
 
SOLUTION 2:

Use a regular domain account and upgrade to 7.4.30009 then switch to a GMSA account and finish the upgrade to 7.5.