ERROR: An internal error occurred while adding your email address.

ERROR: An internal error occurred while adding your email address.

Hi,
I have been getting this error all day, when attempting to create an email campaign AND automation.
An internal error occurred while adding your email address. Please try again after sometime or contact us at support@zohocampaigns.com to resolve the problem.

What would be the issue and cause this error?

Thanks a bunch,