When adding a custom domain to your project and changing the Nameservers of the domain to use Vercel's one, you may need to add MX records to ensure you continue to receive emails.
By adding MX records, you are providing mail services with instructions for where to send emails sent to your domain. Your domain registrar or mail provider will be able to provide you with a list of records that needs to be added.
DNS Preset
You can use the DNS UI to add a preset for common mail services.
If your email provider is not in the list of presets, you can proceed to next section where we will discuss adding records manually.
Adding DNS Records
While the DNS UI does have a preset for G Suite, it will serve as an example in this article. You can consult the documentation for G Suite here
First you need to insert the MX records related to your service:
You will likely need to repeat this step multiple times, depending on the number of records your provider requires you to add.
The second step is to verify the domain. G Suite is requiring a TXT record so we can verify the domain.
In this case, the TXT should be in the root domain and that is why the 'name' field is empty. You need to check the required arguments with your mail provider.