Export and Features error

I can’t export any typeface anymore.
It gives me this error to the bottom left corner (IMAGE 1)
When I try to export the typeface it says this message (it changes letters every time) (IMAGE 2)
If I go to the features, I try to change something and update it, it gives me this error (IMAGE 3)

3: Looks like a bad name. What is your font called? Did you check for invisible characters in the font name? Perhaps at the end?

2: What does your glyph C look like? Perhaps use Show Angled Handles and Red Arrows to analyze the paths. Get the plug-ins from Window > Plugin Manager. How wide is the glyph? Removing Overlap does not work if the glyph width is more than 8190 units.

What version of macOS and what version of Glyphs do you have?

My font is called Savage and it have two versions: normal and fury. It doesn’t seem to have invisible characters in the font name or at the end of it. I already exported it in the past, I found this problem after making the kerning groups.

It is like a sans serif C. If I export it, one time it say the problem is the C and other time is the A etc, so I don’t think that the letter is the problem (if I delete all letters it says the problem is the .notdef glyph). However I have tried to download the extension but it can’t currently work.

I suspect you have updated to MacOS Catalina but not to the latest version of Glyphs. That can cause those problems.

Yes I have Catalina but not the latest version of Glyphs.

I am getting this same error message, have updated both make and glyphs mini app.

Any ideas on how to resolve?

That can be caused be a few things. Most likely by an invalid character in a glyph name or font name.