If your mail services were disabled automatically:
and/or your email account appears as Suspended, there are two possible reasons:
You can enable mail services manually, although they can be disabled again if the root cause is not eliminated.
How to avoid email account suspension?
First of all, if your website has a contact form, make sure to add a CAPTCHA to it - this way you will prevent bots from sending mass spam emails.
Also, unwanted and unintended emails sent from the account might also be caused by malware on the website, so it’s highly recommended to make sure malware is removed before enabling email services again.
If your email account’s sending is disabled, sending new emails through email clients and devices will not be possible as well