Some DNS providers restrict the number of characters that can be placed into a TXT record. You can use the Email Deliverability feature in the cPanel interface to split the suggested DKIM record into 255-character parts.
- Log into cPanel.
- In the "Email" section, click "Email Deliverability."
- Click "Manage" to the far right of your domain.
- In the section "Suggested “DKIM” (TXT) Record," next to the "View" option, select "Split."
- Click the "Copy" button to copy the split record to your clipboard.