Good morning. I'm having a terrible, terrible time with a problem that seems to me like a bug. I've edited several DNN pages by way of making copies of them, then editing the copies with the intent to re-use the URL to simply point to these new pages. I've done so by deleting the OLD pages, but I'm still getting the "  " message. This is so ridiculously frustrating I can't begin describe it. IF anybody has any suggestions on a workaround and an explanation as to why this is happening, I'd appreciate it. Thank you very much.

Thanks for sharing. I just ran into the same issue and it was also a page in the recycle bin.
The error message isn't very helpful.