Nextcloud 13 Internalisation serveur error

I’m new here and I used nextcloud for my personnal data. I have an issue when i update php5.6 to php7. Then i can’t access to my nextcloud. I see this text on the front :

"Internal Server Error

The server encountered an internal error and was unable to complete your request.
Please contact the server administrator if this error reappears multiple times, please include the technical details below in your report.
More details can be found in the server log."

Someone have the same issue and can help me to solve it please ?

Thank you for your help.

I resolve my issue. Just in case someone had the same issue you will find my solution below:

When i upgrade PHP5.6 to PHP7 i forget to reinstall php-apcu for OPcache :

I follow this tuto

And all it’s ok.