Make sure your internet is connected and working.
Make sure that your email settings and password is correct as per the instructions provided by your hosting company. (contact your hosting company for support)
If the email issue hasn't been resolved with steps 1 and 2 Make sure that your computer is clean and not infected with viruses.
- Scan your computer with Malwarebytes.
Make sure that your antivirus, if you have one installed, isn't blocking your email server.
Contact your email hosting company and inquire if it's possible that your IP address isn't blocked by their servers
NOTE: Always keep your local machine software up to date and make sure that your computer is scanned once a week for viruses and malware with the appropriate software. Recommend to use Malwarebytes (free to use program)