Unable to progress with the ritual quest

I'm on the part where I have to complete rituals in Rite of the Nameless Maps to collect 5 items. I got 4 of the items and failed the final ritual encounter, so the last item did not drop. That was also the last map in the chain.

Since then, I farmed another audience with the king, explored the atlas to find another crux of nothingness, killed the boss again for another head of the king, and it says to go to Caer Tarth to start a new chain of maps. At first, I didn't see any way to start a new rite. But then I tried relogging, and I can see in the middle there is something to click to start it, but as soon as I move, it disappears.

Does anyone know a fix for this? I'm completely stuck.