The recipient was rejected by the sever – Mail on Mac & iPad

I'm having a problem setting up my Bluehost email on my mac and ipad. My email settings work on the Thunderbird client, but I want to use Mail to sync everything.

* iPad

Cannot send mail to my @me.com address, specifically.

I get the message The recipient was rejected by the sever.

* Mac, Lion OSX.

Can't send or receive any email using Mail.

I did a Terminal check, but don't know how to read it:

biff = no

command_directory = /usr/sbin

config_directory = /etc/postfix

daemon_directory = /usr/libexec/postfix

data_directory = /Library/Server/Mail/Data/mta

debug_peer_level = 2

html_directory = /usr/share/doc/postfix/html

imap_submit_cred_file = /etc/postfix/submit.cred

inet_interfaces = loopback-only

inet_protocols = all

mail_owner = _postfix

mailbox_size_limit = 0

mailq_path = /usr/bin/mailq

manpage_directory = /usr/share/man

message_size_limit = 10485760

mydomain_fallback = localhost

mynetworks = 127.0.0.0/8, [::1]/128

newaliases_path = /usr/bin/newaliases

queue_directory = /Library/Server/Mail/Data/spool

readme_directory = /usr/share/doc/postfix

recipient_delimiter = +

sample_directory = /usr/share/doc/postfix/examples

sendmail_path = /usr/sbin/sendmail

setgid_group = _postdrop

smtpd_client_restrictions = permit_mynetworks permit_sasl_authenticated permit

smtpd_tls_ciphers = medium

smtpd_tls_exclude_ciphers = SSLv2, aNULL, ADH, eNULL

tls_random_source = dev:/dev/urandom

unknown_local_recipient_reject_code = 550

use_sacl_cache = yes

Also, I can't figure out how to change the incoming port, as it may be a solution....

I have checked the settings (copy and pasted for each). The fact the Mac and iPad behave differently bemuses....

Please advise.