Configure your DNS
DNS records tell mail senders which service handles incoming email for the domain. They are usually set at the domain provider from which you acquired your domain.
Here are somes guides which might help you:
Alternatively we can do that setup for you if you subscribe to a premium plan. We'll need your registrar credentials so we can access your DNS editor.
Try with an empty field instead, or with your domain name.
Add MX record
Login to your domain provider, delete any existing MX records in the DNS editor, and add this one.
Host / Name Value Priority @ mail.postale.io. 0
Add TXT records
Delete any existing TXT records for SPF, DMARC, and DKIM, and add these three. They will help your emails avoid SPAM folders.
Please specify a domain for DKIM and DMARC:
Host / Name Value @ v=spf1 mx ~all