Sorry for the late response. Somehow I never received notifications for a few threads. I’m finding them now here and catching up on all missed questions.
We push a big update earlier today that should solve the /amp/ issue. Could you update PageFrog and try again?
In my site its was working until now isnt.
all /amp/ redirect to the original.
With /?amp it displays the AMP page correctly.
The problem still persists. However, Google Search Console has indexed a couple of AMP pages. Maybe they check for “/?amp” too?
I am having the same problem, I am just unsure if it is PageFrog-related. I tried disabling this plugin and leaving only the Automattic AMP, but still the same. I can see the AMP page with ?amp=1 but not with /amp/ or /amp permalinks.
I am getting 404 errors when using the /amp/ permalinks 🙁
I confirm, I have same problem
I got it to work after disabling/re-enabling all the amp-related plugins, and changing a couple of times my permalinks, then back to the original format. Strange, but it worked.