To add a custom tracking domain on Ionos domains:
Go in the Domains section of the Control Panel, next to your desired domain, click on the gear symbol under Actions and select DNS
Click Add Record and select the CNAME type
Enter the following details:
Hostname: inst
Points to: prox.itrackly.com
Click Save
Go to your email account settings in Instantly
Click on ‘Use custom tracking domain’
Add the new CNAME in the Instantly settings and click on ‘Check Status’
Add it as inst.yoursendingdomain.com in Instantly with yoursendingdomain.com being the domain you added the CNAME record under
If everything is set up correctly you will receive the following notifications below the Check Status button
CNAME Verified, SSL Verified
6. Go ahead and save changes