Ue4 Packaged HTML5, Open with a Nightly, Start Engine Error

Trouble to help me deal with it!
Ue4 Packaged HTML5, Open with a Nightly, Start Engine Error.
I don’t know if it’s a problem with “Failed to openIndexedDB”. If so, how should I solve it?

Hello,

We’ve recently made a switch to a new bug reporting method using a more structured form. Please visit the link below for more details and report the issue using the new Bug Submission Form. Feel free to continue to use this thread for community discussion around the issue.

https://forums.unrealengine.com/unreal-engine/announcements-and-releases/1410408-unreal-engine-bug-submission-form

Thanks