Internal Error during install

When I try to install Dolibar I got this error. I have checked permissions, I have created a conf.php already.
I have tested that I can access to htdocs folder by placing an index.html inside and reading it from browser. It seems it comes from reading index.php that I get this error. the file is in 644. I have created documents folder too.
The strangest is I have another instance with another install on the same server that work perfectly…

# Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator at to inform them of the time this error occurred, and the actions you performed just before this error.

More information about this error may be available in the server error log.

Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.


Error 500 = PHP error => Check your hosting logs.