Ubuntu: 'Not Found' error on restore

I’m trying to restore the test of my backup that I made and it fails with “Not Found” right when I enter ‘Restore’ (without even trying to do actual restore)
When I check where is the problem while examining requests that are being sent by UI I see 404 error for this get request:
http://[mydomain]/api/v1/backup/1/files/%2F?prefix-only=false&folder-contents=true&time=2020-04-02T23%3A37%3A08%2B03%3A00&filter=%2F

Similar request that was sent right before this one works fine:
http://[mydomain]/api/v1/backup/1/files/*?prefix-only=true&folder-contents=false&time=2020-04-02T20%3A52%3A30%2B03%3A00
So I assume there is an issue with ‘/’ being added there?

I’m accessing duplicati UI from remote address by apache proxy to 127.0.0.1:8200

So, I figured that I can access duplicati without apache proxy trick and it works fine without it if I just enable remote access and load through http://[mydomain]:8200/
Must be an issue with apache