I now did a downgrade to 6.4.4 and it seems like i can switch there
between captive portal and self service under Policies. And this
directly from scratch without any configuration (was definitively
missing before), so looks like a bug in 6.4.5
I have exactly the same issue here, FortiAuthenticator in a LAB
environment to test the Captive Portal functionality. But I don't see
the toggle option under Authentication > Portals > Policies I also asked
for an Eval license in case something is on...