Hi, as you facing the issue with fax sending . I would suggest you to check some fax send settings under fax send setup as follow:
Def. Resolution
Def. Light/Dark
Def. Glass Size
Dialing Mode
Redial if busy
Redial-no answer
Redial Comm Err.
Dial Prefix
Detect dial tone
Billing codes
If the error persists contact HP contact center for hardware issue (fax card).
Hope this helps .
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