I installed gallery3 opensource then i want to place the internal address using external sites but it display a blank page
but if i access directly the address i can able to see webbased of gallery3.
thanks
Good morning,
this is most probably caused by Nextclouds security restrictions like
Please check the browser console (firefox press f12,switch to console and re-call your url), what is shown if you call your gallery3 url within your Nextcloud?
Load denied by X-Frame-Options: https://gallery3-url/ does not permit cross-origin framing.
… it is not a bug, it is a (security) feature 
cheers, carsten