Random Error logging into site

Just recently I can only log in to my admin account very infrequesntly.
I get the following error

Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

If I do get logged in, this error will occur when navigating on the admin pages as well


Do you know if your host recently made any changes?
Is your installation of Backlight up to date? What version are you using, BL4 or BL5?
What version of php is your host using? you can find out by going to Backlight > Admin > Special links > View PHP Info
(assuming you can log in)

This now appears to have been a temporary issue with my ISP.
FYI to answer your questions,
BL 5 with all the latest modules
PHP 7.3

Thanks for the quick response