It sounds like your preview link is set to "Brand internal only" which will require a login https://www.qualtrics.com/support/survey-platform/survey-module/preview-survey/#SharePreview

Evaluation ..Thanks for sharing the link, it is very helpful.

I have my Preview Links for several surveys set to Public. All of the links are redirecting to the login page. Can someone help me troubleshoot?

https://community.qualtrics.com/XMcommunity/discussion/comment/51325#Comment_51325I had the same issue last month and submitted a ticket to Support and was told that this was due to internal platform issues that the engineers were working on.
Perhaps they have the same issue again?

Just tested it on my side, and I'm not prompted to log in. I would submit a ticket to Support.
Good luck and feel free to revert back with what they came back with.
All the best
-Mattias

https://community.qualtrics.com/XMcommunity/discussion/comment/51327#Comment_51327I'm pretty sure it is a browser cache or cookie issue. If you preview before changing to public the browser remembers so even after you've changed the link to public it still thinks it is brand internal. It works if you use a Private/Incognito window, a different browser, etc.

https://community.qualtrics.com/XMcommunity/discussion/comment/51328#Comment_51328I'm no expert, I just know it started for a whole team I was testing a survey with.

The Qualtrics Chat agent is working on it with me. This is happening with others who are outside of the Qualtrics platform and have never tested the links before.