have you double checked the pop and smtp settings to ensure they are accurate to the providers email server?

databaseben said

have you double checked the pop and smtp settings to ensure they are accurate to the providers email server?

Yes, I checked

there is just too much to consider when it comes to "cant send email".

try logging into the web email server and check the settings. sometimes you have to give permission for the email program to access the account.

@Stevenquestioner :

If you're running anti-virus software, such as AVAST, would you please disable it and see if that makes a difference  ?

Also see the article :

Cannot send messages