I have found the error that did not allow me to reload rooms. The new updates show that Gamemaker has added a null variable to my object. As I have this object in all the rooms, it is corrupted in all of them.
{"resourceType":"GMOverriddenProperty","resourceVersion":"1.0","name":"","propertyId":null,"objectId":{"name":"objParallaxGeneratorBackgroundV3","path":"objects/objParallaxGeneratorBackgroundV3/objParallaxGeneratorBackgroundV3.yy",},"value":"10",},
As for the reload code of the objects, I can't replicate it, but I get that error code in the main character when I reload it, I can't figure out where the problem is, but I know that in the previous version, when I changed part of the code of the steps in the character, things stopped working.
I will continue investigating and let you know if I find the solution in case it is my problem, thanks for your help.
EDIT: I found the error, I'm using accents whether in regions or commenting code, or even in Strings, In my language it is normal for comments to have accents:
#region Animación mochila
//Code
#endregion
//Partículas jugador
EDIT2: The special characters i'm using are these:
á, é, í, ó, ú