First, try going to "webmail" and sending from there. If so, check your settings in your Outlook, phone, etc.
If you run across the error message below, preventing you from sending emails via webmail, please submit a help request (links at top and bottom of this page) and mention the email address or addresses you receive this error message for.
User not permitted to relayThe following recipient(s) could not be reached: 554 5.7.1 : End-of-data rejected: user not permitted to relay
This type of error may occur because of a broad range of reasons, but most commonly it is when the email service provider has received numerous recent reports of spam coming from your email address. This can happen due to a virus on your system, a hacker using your password to send mail from your account, or if you try to send mass emails from your email account (use the newsletter feature for that or contact us for other alternatives, don't do so from your regular email account.)