To get to the account settings screen, click Tools near the top left of Thunderbird and then click Account Settings.

This will bring up the Account Settings window. From here find the account you are looking to edit on the left and click Server settings beneath it. This is where incoming settings are adjusted.

Fill in the fields accordingly:
  • Server Name: mail.bluevalley.net
  • Port: 993 for IMAP, 995 for POP (Account type is listed next to Server Type at the very top of this screen.)
  • User Name: Full email address (ex: john@bluevalley.net)
  • Connection Security: SSL (Or SSL/TLS)
  • Authentication Method: Normal password (Or Password, transmitted insecurely
Click Outgoing Server (SMTP) at the bottom of the left-hand column.
This will bring up a list of outgoing servers listed in the small white box on the right, one per email account generally. Most people will only have one in here, some customers who have multiple email accounts will likely see one for each account and they will each need to be adjusted manually.
Begin by selecting the account in the white box that you want to edit and click the Edit edit button to the right. A small window will pop-up with all of the relevant outgoing server settings we need to adjust.

Fill in the fields accordingly:
  • Description: Put the email address here to identify the account.
  • Server Name: mail.bluevalley.net
  • Port: 587
  • Connection Security: SSL (Or SSL/TLS)
  • Authentication Method: Normal password (Or Password, transmitted insecurely
  • User Name: Full email address (ex: john@bluevalley.net)

Click OK, then click OK again to close the account settings window and apply all of the changes. (Unless you have more accounts to adjust, of course.)
Incoming (IMAP)
Server: mail.bluevalley.net
Port: 993
SSL: Yes
Username: Your full email address

Incoming (POP)
Server: mail.bluevalley.net
Port: 995
SSL: Yes
Username: Your full email address

Outgoing (SMTP)
Server: mail.bluevalley.net
Port: 587
SSL: Yes
Authentication: Enabled