Hey Navsin, POP and SMTP are separate protocols (POP for receiving and SMTP for sending) and both probably require authentication. It looks like your POP (receiving) may be working but SMTP (sending) isn't. Try this: Go to your account settings (Mail->Edit Accounts) and select the account you're using for POP. Scroll down to where it says Outgoing server (SMTP), and make secure Secure Authentication is turned on (it should say None, Login, or CRAM-MD5). You probably need Login. Then, enter your username and password right below that. Save, and retry send/receive. If it still doesn't work, go back to the same place and check if Secure connection is enabled. There are 3 settings - None, Normal (TLS) and SSL. Try the last two (TLS and SSL). Might also try switching the port around from 25 to 465 to 1025. One of these should work for ya.