If your Nameservers are Pointing to Wix and your Emails are hosted with 1-Grid, You will need to Edit or Add the Email record so that it can point back to 1-Grid
Step 1. Go to the Domain page in your Wix account
Step 2. Click on the Show more Icon next to the domain and select manage DNS records
Step 3. Go to add Record you would like to add eg: Cname, MX records, A Record or TXT and add the record in there
Step 4. Enter the DNS record Eg: mail.domainname.com – For Emails please enter the IP address you would like to point your emails to Eg: 41.123.123.123
Step 5. Click Save
Step 6. Click save changes in the popup box