Mybee interessting fact i found out with the case that the Portal is not working....
I found following Info on the Apple Side:
DHCP Option: 114 (Captive-Portal)
Length: 38
Value:
https://example.org/captive-portal/api
DHCPv6 Option: 103 (Captive-Portal)
Length: 38
Value:
https://example.org/captive-portal/api
IPv6 RA Option: 37 (Captive-Portal)
Length: 38
Value:
https://example.org/captive-portal/api
So i created follwoing DHCP Option for my Hotspot DHCP Server:
/ip dhcp-server option
add code=114 force=yes name="Captive Portal" value="'http://***IP Hotspot Bridge***'"
add code=160 force=yes name=option1 value="'http://***IP Hotspot Bridge***'"
/ip dhcp-server option sets
add name=set1 options="Captive Portal,option1"
Than i had to go to the DHCP Server and activate the DHCP Option.
After this i greated an Walled Garden deny rule.
(iOS is checking captive.apple if there is internet on the connected WLAN)
add action=deny dst-host=*captive.apple* server=****HOTSPOT-SERVER-NAME****
Than move this rule to 1st positon.
Since than my Hotspot Portal is back working on all iOS devices.
Maybe it will help some others.
Info from Apple regarding DHCP Options:
https://developer.apple.com/news/?id=q78sq5rv