Mikrotik Hotspot problem - Walled garden NAT

Hello,
I have problem with hotspot. I want to authorize hotspot clients through external server. Now i`m using walled garden, but mikrotik uses proxy and client is behind proxy when communicating to external server.

So I want to bypass nat/proxy for some destination adress in mikrotik hotspot. Is it possible?

(I tried to edit nat rules but I wasn`t successful.)

Thank you for help..

Look at the hs-unauth chain in the NAT. You should be able to make a dstnat rule manually and insert it before the redirect rule on http and https packets.