Ahh okay, got the issue.
Go to phpvms_aircraft table -> Structure -> Select these two columns : 'airline' and 'location' -> CLick on change at the bottom -> Set Default for both as NULL in the dropdown.
That should solve the issue.
Are you using HTTPS? Did anything change there? Connection timed out means there's an issue between the ACARS and site. Are you the only one having the issue?