Mixed-Content Blocked by Chrome & Firefox

I currently have Nextcloud running on the latest SNAP on a Ubuntu 18.04 vm and an OnlyOffice document server running on a seperate Ubuntu 18.04 vm. They are both behind a Netscaler that’s doing content switching for all of my subdomains and SSL offloading for the OnlyOffice server. Whenever I try to edit a document, I get “Requests to the server have been blocked by an extension” and looking at the developer console shows the request was blocked because an https page tried to request an http page from my onlyoffice document server. I have all https URLs in my OnlyOffice settings page in NextCloud. Any ideas?

I met the same thing, has someone fixed it yet? please guide me. Thank you!