Hello,
i need help please

i can access my back-end slave, i can modify all, but in front-end not display anything, just this:
The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, postmaster@xxx.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.

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

may you help me?
thank you

In general an Internal Server Error may be due to a permission on a directory that is not correct ro similar.

If you have a "erro_log" file on your disk, perhaps it will give you more information on the reason

thanks for the reply
You have already solved this problem before?
if you pay for one hour, you can fix this problem?

JSM multisites I use for a large project

thank you

YES we already encountered such cases and solve them with billable support.

The latest case that we had were a website that use SEF and .htaccess.
If your website is working without SEF, this may be a problem in rewritebase value in the htaccess.