Emails to gmail failing authentication from my own domain via BTInternet.com mail

[licquorice]

That's ridiculous, who's your domain provider?

[wrighar]

To clarify, I have a domain   mydomain.org  which has nothing other than 3 or 4 email id's

I use Thunderbird to send emails from aaa@mydomain.org using my BT Fibre and BT email account mail servers.

Incoming email from mydomain.org are forwarded to myBTemailid@btinternet.com

Thunderbird the filters to mailboxes based on original email id

[wrighar]

Freeola 😞

[licquorice]

You get what you pay for!

[licquorice]

For £6/m with Ionos (1&1) I  get my domain, website hosting, 50 email addresses with SMTP and IMAP server access.