Cannot log onto account

Hi, I am totally new to EmClient and I cannot seem to open the account, i keep getting this message -

[SMTP] Cannot send message (Sending email “test” failed with error: ‘From’ field address ‘[email protected]’ not accepted due to the following reason:
"5.7.57 Client not authenticated to send mail. [LO4P123CA0365.GBRP123.PROD.OUTLOOK.COM 2023-06-27T10:35:47.245Z 08DB768847B97197]
It is a free account, any top tips to get it working will be gratefully received.

You can no longer use email applications with BTConnect email accounts. They now only allow webmail through your browser, and I think one specific phone app.

Probably you missed their emails to you about that, so here is their announcement again.