I have a group of about 250 people that I regularly email for an amateur society. I have had to split these into small groups of 30 otherwise my account tells me I've exceeded my authorisation and I have to reset everything. Now I have just sent them in those smaller groups and got the message "Message rejected as it apepars to be spam. Use STMP AUTH, post office or contact the postmaster". This has come for 3 of the 7 groups but not all of them.
Why has this suddenly started happening, it is very tedious.
Welcome to the Community!
There are restrictions set for the security of our mail server.
May we know the Email client that you are using? Have you tried to change the email account password, then try again?
Please send me a PM with your TPG username or customer ID number along with the email address that's experiencing the issue.