I have a 751U-2HnD and I am trying to setup a Hotspot Server. I already followed this wiki http://wiki.mikrotik.com/wiki/Hotspot_server_setup. I also upgraded it to v6.0rc12. I am trying to setup the Hotspot on the wlan1 interface. The problem is that once the Hotspot is created, it is shown as invalid and the text is highlighted in red but internet access is ok (I can browse normally but the login page isn't shown). I tried many times by resetting the configurations and start from scratch with no success.

When I tried to change the interface from wlan1 to bridge-local, the Hotspot wasn't invalid anymore but I couldn't access the internet this time.

The main settings are:

ether1-gateway: 192.168.0.10/24
wlan1: 192.168.88.1/24
IP > Routes: 0.0.0.0/0 192.168.0.1
DNS: ISP IP addresses

If you require any further information just let me know.
Thanks

If you have added interface to bridge then you must operate with bridge interface and setup Hotspot on bridge interface.
IP address must be assigned to bridge too.
Otherwise use regular interface (wlan1?).

the bridge interface was there by default when I did a system reset. I did not add it. it is bridging ports wlan1 and ether2-master (ether2-master is not connected). So are you saying that can disable or remove the bridge interface and set the hotspot on wlan1?

Yes.
You can clear configuration without any predefines Then make setup on wlan1.

well I cleared the configurations as you said, the problem now is that I cannot connect to the router via winbox. I connected the ethernet cable to port 2 (also tried port 1) and to the NIC of the computer and tried to access the router via the MAC address with no success. I also tried to unchecked secure mode but nothing, I couldn't connect. I don't know what's causing this problem.

I am also missing the .html pages such as login.html and logout.html and all others. I only have the folder structure.

Hotspot files...