Sending emails from a Onetel.net address

[HMJUCB]

I receive emails but am unable to send them. I get a 'System Administrator error' message. When pressing 'Send' a box appears with a message 'The server you are connected to is using a security certificate that cannot be verified. The target principal name is incorrect.'

I have attempted to rectify this with Talktalk through the online BOT, real people after the BOT and on the phone several times. The process ceases without satisfaction. Hours spent so far without success. Does anyone have any ideas please?

[Ady-TalkTalk]

Hi ER_R001_001314_1, please start a new topic and provide as much information as possible.

Ady

[ER_R001_001314_1]

Yes, I received a couple of emails from Talktalk around midday today after I accessed the Community site.

[Ady-TalkTalk]

Hi HMJUCB, I've added your details to the existing incident for being unable to send. Did you recently receive and open an email purporting to be from TalkTalk?

Ady