I'm working with the Altium Designer version 20.2.4.
I'm using only 2 libraries. The first has only one component, a microcontroller from ST. The second is a library where another person put a lot of passive and active components, schematics and footprints with 3D models.
I've created 4 schematics and 1 PCB document to work on them. I've compiled the only schematic where I have put the micro and some passive components, and I can view them in the PCB document with no errors, but then when I try to add some new components, the same or other from the libraries (or from the miscellaneous internal library), the console throws errors with the nets and with the class of the recently added component. The errors are the following, when i.e. I try to put a new capacitor to the "MICRO" schematic:
I have watched a lot of official tutorials from Altium, and have read a lot of documentation, but I can't solve the problem. I think all the footprints are well associated with the schematic components, which is one of the "solutions" that the people talk on internet.
I'm really new using this program, so maybe the solution is more simple than I think now, but I'll be grateful if someone finds out.
If someone needs the project to make some tests, I can put in somewhere it's comfortable.