Have you attempted to make the changes in another browser? If it works, then it's likely a caching issue on the other browser. I've noticed that happens a lot with the DNS Management system. It doesn't like caching for some reason.
If that doesn't work, please contact phone or chat support as it's likely a server-side issue.
I am a GoDaddy End User - Just Like You * Please note that I DO NOT answer private messages. Please ask your question in the proper forum so the answer can assist EVERYONE in the community and not just you. If you contact me via PM for help, I will give you a price quote for my personal services. Thanks! *
Once your issue is resolved, please be sure to come back and click accept for the solution