I've been running an Osticket system for over 2 years. There's never been a problem with it. This week I wanted to set up a new second one and am having the same problems as you. All of your suggestions didn't help. The system is configured 1:1 like my first one, I have now reinstalled it 3 times and configured all the settings. It's strange that so many people are having this problem recently. But it only affects new installations. As a test, I installed 1.17.x, which I started with back then.