If this happens after update to v3.2, you maybe need to clear the browser's cache.
(I also had to do this on my mobile)
On Windows/Linux, try to reload the page with [Ctrl]+[Shift]+[R] or [Ctrl]+[F5] or open up the clear-browserdata-page with [Ctrl]+[Shift]+[Del].
On mobile, you need to clear the cache in the privacy settings.
these did not work, even mobile, different machine/browser i still have this issue. also it seems that after a while the service for pihole fails on the interface and shows Lost Connection to API, even if the service says its running in ssh.
I am running this on a VPS (OVH) and have had it run fine before. not sure what is going on with it now. seems like it just broke. if anyone can tell me other things to try, im all for it. I have uninstalled/reinstalled several times now.