Not receiving mail - reported as spam

[Mallad]

One of my btinternet email addresses has stopped receiving mail (Outlook365 on PC). It has been working for years.  I can send mail from this address using Outlook and webmail is absolutely fine - there are many messages.

I sent a test mail with no content to this btinternet address from gmail and got "message not delivered - the response from the remote server was your message looks like spam, or has been reported as spam",

Any ideas?

[Mallad · Accepted solution]

fyi this only happened once. One day's emails, for one address never got downloaded to outlook and had to be processed on webmail. All appears back to normal