Errors when sending or receiving email in Outlook.com or Hotmail

Here is the error message, this started a week ago. Am able to receive emails but ones sent are not going through.

Delivery has failed to these recipients or groups:

@aol.com (@aol.com)
Your message couldn't be delivered. Despite repeated attempts to contact the recipient's email system it didn't respond.

Contact the recipient by some other means (by phone, for example) and ask them to tell their email admin that it appears that their email system isn't accepting connection requests from your email system. Give them the error details shown below. It's likely that the recipient's email admin is the only one who can fix this problem.

For more information and tips to fix this issue see this article: https://go.microsoft.com/fwlink/?LinkId=389361.

Diagnostic information for administrators:

Generating server: PH7PR16MB6144.namprd16.prod.outlook.com
Receiving server: PH7PR16MB6144.namprd16.prod.outlook.com
Total retry attempts: 4

******@aol.com
2/9/2024 1:14:41 PM - Server at PH7PR16MB6144.namprd16.prod.outlook.com returned '550 5.4.300 Message expired -> 421 4.4.2 Connection dropped due to SocketError'
2/9/2024 1:11:22 PM - Server at mx-aol.mail.gm0.yahoodns.net (98.136.96.92) returned '421 4.4.2 Connection dropped due to SocketError'

additional information. windows 11 office 365. The mail arrives properly but will not send it. All mail remains in the outbox. problem started 10 days ago. my internet provider gave me your number to call. None of my emails had attachment. Thank you. 2 of 2 problem descriptions today Anne.

windows 11, MS 360

Hi,

I have trouble sending emails on my account

I am unable to send email on my Shaw account or my hotmail account using outlook

I am able to send email if I log into Shaw webmail directly.

I am receiving emails fine on both accounts

I can receive emails but I cannot send them. They go into the Out box and are impossible to send.