you can try to change your mail sending method under events > settings > emails > email settings > mail sending method eg. WP Mail, PHP Mail or use smtp then your gmail account to rule out any mail server issue.
I have done. But Its does not work
Same error are coming for all mail function
If none of the mail sending methods work, it sounds like you may have a configuration problem with your web server.
Do you get other email notifications from WordPress (for new comments, etc.)?
No there is no email ,I had got from wordpress.
If you’re not getting any emails from WordPress then it sounds like a configuration problem with your web server. You’ll need to contact your web hosting support for help with fixing that.
