Fax landline can dial out and send faxes but always rings busy on incoming call or incoming fax. Any suggestions on how to fix problem? Thanks.

Unplug anything into fax line and see if it rings or rings busy. If it rings busy it usually means the phone is "off hook" or shorted.
If it rings busy with fax plugged back in, Fax may have a problem. Maybe try unplugging power to fax, then plug back in.