Hi @KR34T1V
Use TAIGA_DOMAIN=taiga.domain.com
in the .env file instead of TAIGA_DOMAIN=taiga.domain.com:9000
. Then restart Taiga and try again.
Your browser has to connect to port 443 where your nginx listens, which is what performs the proxypass to port 9000.
I hope this can help.
Best regards