What the error message says would be helpful.
Also, can you log into your server and delete the message there?
I.E. if your e-mail address ends @btinternet.com - you can log into bt yahoo - mail - inbox - and delete the message.
OnePlus 5 review
Alice Saey's mesmerising animation for Dutch singer Mark Lotterman
iPad Pro 10.5in (2017) review
Comment booster votre iPhone ?