Is info@buysellcyprus.com your actual email address, or is this an alias for the real address? I ask because SMTP servers will reject an email id that isn't recognized as a legitimate user. This can also happen for other reasons, but checking SMTP settings would be my first check.

Thanks for the reply David, No buysell.com it is not my e-mail address. Every e-mail I try to send or answer keeps coming up with " Relay access denied. Please check the message recipient "" and try again Any further help would be apreciated Sue

Please check your SMTP server settings. It needs to show your real email address and password.

I have checked the STMP server settings and they are correct

Where do you have enteed the emai address of info@buysellcyprus.com ?

That has nothing to do with the problem, I was just trying to respond to their e-mail to me. My settings for both accounts are shown correctly on my settings

Well, it may help if you post a screenshot of the SMTP server settings. Another possibility (which I see somewhat regularly) is having multiple accounts on Thunderbird and accidentally using the wrong SMTP server for an account. This URL gives a basic overview of the relay issue and that is why I am still puzzled about the info@ email address in the message that you say isn't yours. https://bobcares.com/blog/554-5-7-1-relay-access-denied/