the exception you posted seems to be a time out issue - wither the connection is lost or the FirstSpirit server didn't answer within the allowed time.
Since you wrote, that there are issues with the SiteArchitect, too, I assume that the problem is located within the FirstSpirit Server.
You wrote that the problems begun after you updated FirstSpirit and the JDK. If you use a very old server installation, maybe the root cause of the problems are the used start parameters or an old wrapper version isn't working well together with the JDK 11.
You should create a ticket for our tech support, so that the problem can be analysed (and solved) there.
Maybe (just a guess, since I don't have sufficient information) you can solve the issue by updating the wrapper (FirstSpirit backend) and the start parameters. Instructions how to update the backend can be found here:
But for very old FirstSpirit installations the fs-wrapper.isolated.conf (or even the fs-wrapper.conf, if still the legacy mode is used) has also to be updated. You can find an up-to-date-version of the file within the fs-install-2.1.0.tar.gz.
But be careful - you must manually transfer the important settings (java.command, java.maxmemory, java.initmemory) from the current version to the new version and maybe some of the java.additional commands, if there are any special parameters for the server installation.
Since it is possible, that the FirstSpirit server will no longer start, if you make a mistake, once again the hint that you should create a tech support ticket 🙂