If your computer went to sleep, your session would have timed out due to inactivity - what’s your session expiration timeout set to? https://docs.moodle.org/37/en/Session_handling#Timeout
What makes you think Moodle is not handling the session properly?
Are you using database sessions or server disc based sessions?
But your site seems to be back up and functional (although in maintenance mode) so at least you’ve got past the internal server error messages. Who is your hosting provider? What is the spec of the hosting package? What version of Moodle, MySQL, OS, etc are you using?
What makes you think Moodle is not handling the session properly?
Are you using database sessions or server disc based sessions?
But your site seems to be back up and functional (although in maintenance mode) so at least you’ve got past the internal server error messages. Who is your hosting provider? What is the spec of the hosting package? What version of Moodle, MySQL, OS, etc are you using?