Can't send free-online emails through Apple client

[#1]

I had problems earlier in the week when Plusnet told me to change password & c because they thought account had been compromised. I now can't send emails through my email client, and have difficulty receiving. I can't update/correct the client settings because I get a message 'Unable to verify account name or password'.

[#2]

What version of Apple Mail is it? Also is it a POP or IMAP connection?

[#3]

It's POP.

When I try to correct the settings, it refuses to save them as it says my user name and password can't be verified.

[#4]

And it's Apple Mail 10.3

[#5]

Two points...

1. SMTP server should be port 587 not 25
2. SMTP server on ports 25 or 587 do not use TLS/SSL they use STARTTLS - though it is not clear what Apple Mail does under the covers

You could try...

1. Remove the encryption setting from the SMTP server and see if that works
2. Attempt to connect the SMTP server on port 465 - though this is deprecated, it tends to work and will use TLS/SSL

[#6]

Right, I've changed them, but now am getting a new error message when I try to send a test message to myself…

[#7]

Have you removed authentication on the SMTP server configuration?

[#8]

I did, and it makes no difference…

Thanks for all your help.

[#9]

I've had a look and which settings are you using in particular for SMTP?

Also try deleting the other SMTP server which is labelled SMTP (Offline). 

Apple Mail tends to get confused when there's multiple servers added. 

[#10]

Removing authentication (not to be confused with encryption) will give rise to the exact error message you posted.

Connecting from off the Plusnet network is called relaying. Unless the connection is authenticated (uses user name and password in the SMTP server) you will not be permitted to use (relay via) Plusnet’s SMTP server.