Yes, it is a custom doctype, first thing I did was to clear the cookies but that didn’t solve the issue, I have also tried with another browser and device, but the same error keeps poping up.
maybe somehow the admin user got linked stucked with the custom doctype which no longer exists?
I will try creating a new one with the same name to see if that solves the issue.
Yes the next step is to create a dummy doctype with the same name you have used before using the other admin user
It worked, it seems that everything is back to normal, I will test a little bit and post if something is not working properly.
I don’t really know what happened or why the error was happening but I am glad that at least I can see the information in the system.
Thank you very much for the help and time you spend looking at my issue @centaur @bkm
I will start creating the backups now 