Internal Server Error: concurrent request output

Dear Friends,

after executing any request and trying to see output i receive the error "

"

Internal Server Error

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

Please contact the server administrator, Administrator@xxxxxx.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.

"

this issue happen for any request.

note:

i checked the request output into the appropriate folder and notice that report was created successfully

also after running the request, the status shows "completed"