TREX admin docs - HTTPHEAD failed for URL

Hi,

I handle TREX system the first time. Could you please share with me the  BASIS admin activity docs and Article compilation related errors to outside users when they access. Is it possible to provide https access to them?

preprocessor.cpp (03980) HTTPHEAD failed for URL   ..HANDLE: DISPATCH - Processing document with key '00000006353 failed, returning PREPROCESOR_ACTIVITY_ERROR (code 6401)

I will appreciate all your help and guidance

Thanks a ton