The file name pattern is like this ;
When it's getting longer, this issue happens.
For example,
When user email is ass880821@gmail.com, I got this error. (* fake mail)
When user email is much longer like ass880821@gmailgmailgmailgmail.com, I got this error.
I think there's a limitation on hotspot url length, or.. something not supported.
There's nothing on the length of hotspot url. "[size=10]https://krpano.com/docu/xml/#hotspot.url"[/size]
If anyone knows this solution, please let me know.