OE won't send

I just came from the malware forum and they pronounced my computer clean so they sent me here. I have OE but for the past week, all my emails will not send. I can receive. I get this error message. An unknown error has occurred. Subject 'States expand efforts to combat 'funny honey'', Account: 'mail.gci.net', Server: 'smtp.gci.net', Protocol: SMTP, Server Response: '554 Suspicious message', Port: 25, Secure(SSL): No, Server Error: 554, Error Number: 0x800CCC6F This email was sent to my son. I copied an article to send him. Since this message, no others have gone out so I have 23 emails stacked up in Outbox. I went to MS website for the error number. I followed it precisely and even called my ISP about it and they checked out what I did. They said it was a MS problem. Here is a second error message I got, also on a copied article. I have sent out hundreds of articles before but this has never happened. The message could not be sent because the server rejected the sender's e-mail address. Subject 'http://umichisr.qualtrics.com/SE/?SID=SV_ah3IpkxSDshmVGk', Account: 'mail.gci.net (1)', Server: 'smtp.gci.net', Protocol: SMTP, Server Response: '530 5.7.0 No AUTH command has been given.', Port: 25, Secure(SSL): No, Server Error: 530, Error Number: 0x800CCC78 Thanks in advance for your help.

I just tried disabling Avast and some of the emails went through. Now I am getting this message. The message could not be sent because the server rejected the sender's e-mail address. Server Response: '530 5.7.0 No AUTH command has been given.', Port: 25, Secure(SSL): No, Server Error: 530, Error Number: 0x800CCC78 Thanks GB