iPad as keynote remote. No 'Allow keynote remote' option

Kia ora.

Been using my iphone as a keynote remote to my iPad for years. its great. Reheased my next show and realised I wanted bigger fonts and more space the ipad offered, so decided to use the iphone to host the presentation, and use the ipad as the remote.

But there is no button to "Allow keynote remote" as the help suggests on the ipad.

After trying for an hour and getting frustrated, decided to disconnect the existing link between them.

Didn't help.

So I tried to reconnect them and couldn't because of the same issue. When you follow the guide and go into the more ... button there is no option showing on either device to allow remote control.

Pulling my hair out now!