E-mail problems

When trying to forwad a received email,this error appears on my screen,can anyone
help??

[SMTP] Unable to send message (Sending email “teste” failed with error: Message content not accepted

due to the following reason:

"Attached file ‘Re: ETIQUETA.eml’ has disallowed extension

From translating the screenshot it appears your SMTP mail server has rejected your sent message due to there is a attached .eml message that “either your sending mail server won’t allow” or your sending mail server has “possibly content in the .eml message that is also not allowed”.

So you will need to contact your sending mail server technical support for assistance to see why.

thanks! I owe you one.