when open device security we can't send fax from pc but we can send print job. all combinations are tested from service employee but not resolved.
my version is: 33.50.71
error code: 016-756
I searched our knowledgebase for that fault code and found THIS SOLUTION you can try on your device.
And this is firmware problem. fax permission is not included in the firmware. you must create new firmware. this is bug.