I have they yahoo/verizon email and any email program, other than webmail, will not send or receive. It is not a settings issue as it was working one day...about 3-4 months ago...and then stopped the next day. Also, my sub-accounts will still send and receive...it is ONLY the primary account...so definitely not a settings issue.
Verizon email is horrible..switching over to gmail and ending this horror show.