Well - you made it this far - not much more to do!
You're here because there's one little thing missing. The correct TXT record for your 301 destination.
Your domain is missing a 301 subdomain TXT record.
Use requires the addition of 2 DNS records. One as a pointer to this service, and an additional record as the destination point.
In order to get here you already have the correct CNAME record (or someomeone does...)
14400 IN CNAME redir301.link.
All you now have to do is set the associated TXT record to the destination URL.
301. 14400 IN TXT "<destination URL>"
You're so close.
Go and fix your TXT records and then all will work as expected. Set your TTL on the TXT record to 300 instead of 14400 so you can make sure you get it correct and the cached DNS records here are also quickly refreshed. Nothing happens instantaneously when it comes to DNS!
If you keep coming back to this page, it's probably something wrong elsewhere on your DNS server. Check the logs.