No there really is no IT dept. At least not one you or ANY guest/caller can be transferred to or that the agent can even call and talk to on your behalf. The only options available to agents are open a case, or send you a password reset email or send an email to the app people if it's an app issue and even that forces the agent to be in the middle. Opening a case usually takes several days to resolve and even then it's not going to go to an IT person. Only way it will end up in front of an IT-ish type person is if the agent opening the case makes it clear they've tried every other trouble shooting technique given to them. In almost all cases the problem is on the guests end. I can count on one hand and don't even need the whole hand the number of times it wasn't on the guest's end.

The old spg website used to be terrible to try to get into but the Marriott website seems much much more able to deal with the 50 trillion browsers and such people feel the need to use. Clear your cache. Clear the passwords stored in the browser and that usually resolves the issue.

Trying a different browser will often resolve the issue.

What's the exact place in the process you're getting the error? My biggest complaint with the current website is it doesn't give clear, easy to figure out errors. So you usually have no idea what piece of information needs corrected.