My iMac has Yosemite OS 10.10.5. With the OSX mail app I receive emails from the talktalk server but it refuses to send them saying 'Authentication required (TT401). This started a few days ago sparidically but now I have not been able to send emails for the last two days and it is really affecting my business. I spoke with talktalk's tech support in India or wherever and quite frankly they were useless. They got me to run some pointless tests (their proceedural training) only to say after 15 minutes that talktalk were updating their servers since the cyber attack (which we found out about in the media) and that could be the culprit.
Now, if it is, why did talktalk not inform their customers who pay for this awful service?
And why after so much time, we and I mean many (I've been onto talktalk down dectector) still have NO EMAIL SERVICE?