This article lists some common PHP Fatal Error quick examples that you could find when looking through your Magento logs and the solutions for problems they indicate.
'PHP Fatal error: Maximum execution time of 60 seconds exceeded in....'
You can update the maximum execution time by setting a custom
max_execution_time value in your
php.ini file and redeploying.
max_execution_time = 120
Consult the Customize php.ini settings article.
'PHP Fatal error: Allowed memory size of 792723456 bytes exhausted' (That's just an example byte size.)
php.ini settings. Consult this Customize php.ini settings article.
'PHP Warning: Unknown: failed to open stream: No such file or directory'
Make sure you do not remove the windows-style endings in the
php.ini file. Consult this Customize php.ini settings article.
'PHP Fatal error: Uncaught PDOException: SQLSTATE[HY000]  Too many connections in'
The MySQL environment has run out of disk space. Provide more disk space for the MySQL environment.
'PHP Fatal error: Uncaught TypeError: Return value of Magento'
<root>/tmp directory, because it is probably full. If it is full, provide more space in the directory. This could involve simply moving files to another directory or deleting them.