Export Error: "invalid token"

I tried to export my font to .otf, but it gave me the following error:

Error: “invalid token (text was “+”)” in Class MMK_L_RoundR in line: 0
No File was created. The Reson is unknown.

MMK_L_RoundR is a kerning class I set for several glyphs.
Does anyone have an idea what the problem could be?

I am on OSX 10.5.8 with Glyphs 1.1.8

P.s.: There is a little typo in the error message :wink:

I would need the .glyphs file. Can you send it via mail?

p.s. Thanks for reporting.

I sent an email to info@glyphsapp.com!

You used “+20” as the name of the kerning class. The “+” is not allowed.

Can you open the .glpyhs file in a text editor and replace it with “plus20”?

I will add a check for not valid characters.