If your email stopped working out of nowhere, there might a very simple reason for that - most likely, you have recently updated your domain's nameservers!
Domain nameservers determine where is your domain's DNS zone. For example, if you point your domain to Zyro servers via nameservers, your DNS zone is managed from Zyro. It means that all DNS records, including the ones that are responsible for email service, must be present in your domain's DNS zone (that's now managed from Zyro).
Note: Most of the time, after updating nameservers, DNS records are fetched automatically, however, sometimes they must be recreated manually.
As the Zyro DNS management area is currently under development, all required DNS records can be added by the Customer Success team. Please contact us with the details for the required DNS records (don't forget to specify your domain name!), and we will set them up for you in no time!
Pro tip: If you're not sure what exactly records are responsible for your email service, you may contact your email hosting provider.