Can't connect via SMTP

I’m successfully receiving mail, but not sending. I’ve checked many times, and my settings appear to be correct. Under my STMP tab in the account, I have:
Port: 25
Security policy: Don’t use
Server requires authentication: checked
Use these credentials (and credentials filled out correctly - checked many times)

From the log file:
7:52:03 AM [SMTP] Connecting: To
7:52:24 AM [SMTP] MailExceptions.SocketException: Connect failed with reason:
7:52:24 AM “A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond”
7:52:24 AM at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
7:52:24 AM at MailClient.Smtp.SmtpSendCommand.Execute(WorkerStatus status)
7:52:24 AM at MailClient.Commands.Command.Process(WorkerStatus status)

( is the correct IP address)

I have access to my mail server logs, and it shows no failed attempts to log in by me. I have firewall turned off on my PC.

I know that SMTP is working on that port:

$ telnet 25
Connected to
Escape character is ‘^]’.
220 ESMTP Postfix

Any suggestions?

Solved. Turns out Verizon is blocking port 25.

Hi, I’m glad it works now. Thank you for the solution for other users experiencing this issue.