I am facing the issue after installation QMc and HUB is not opening having some error.
below link i have mentioned the steps which helps to install.
can you share the steps to install QS.3.0.2
Take a look on your schedule tasks or applications developed. Instead of, if you need, restore the backup to understand either the problem is version or other configurations.
I installed on a few customers and upgrade some and there are not problems.
Anyway, try to start only the essential services to be able to understand where is the problem.
Please, mark the CORRECT/HELPFULL comments.