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.
Example
'PHP Fatal error: Maximum execution time of 60 seconds exceeded in....'
Solution
You can update the maximum execution time by setting a custom max_execution_time value in your php.ini file and redeploying.
For example:
max_execution_time = 120
Consult the Customize php.ini settings article.
Example
'PHP Fatal error: Allowed memory size of 792723456 bytes exhausted' (That's just an example byte size.)
Solution
Customize your php.ini settings. Consult this Customize php.ini settings article.
Example
'PHP Warning: Unknown: failed to open stream: No such file or directory'
Solution
Make sure you do not remove the windows-style endings in the php.ini file. Consult this Customize php.ini settings article.
Example
'PHP Fatal error: Uncaught PDOException: SQLSTATE[HY000] [1040] Too many connections in'
Solution
The MySQL environment has run out of disk space. Provide more disk space for the MySQL environment.
Example
'PHP Fatal error: Uncaught TypeError: Return value of Magento'
Solution
Check the <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.