If you are getting the following error in error log, then it might be permission issue with /var/lib/php/session
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Error: PHP Warning: Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/var/lib/php/session) in Unknown on line 0
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This was a known bug in version(s) of PHP . Depending on your server environment, you can try setting the sessions folder to 777:
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chmod -R 777 /var/lib/php/session
chown root:root /var/lib/php/session
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Try it !
