I'm working on a typeface I've been working on for a year and I'm nearly done. Today I added a few more kerning classes and kerned hundreds of kerning pairs. I spent hours on it today and I was excited to be done and generate the font and I get an error stating I can't generate the font because some glyphs used in the feature file were not found in the font.
Now, this seems an easy problem to fix. I just don't know how. Can someone tell me what I need to be looking at? Today I replaced a few characters and added some kerning classes in both Bold and Light and I get the same error in both versions so I'm quite sure the problem is in one of the kerning classes.
As far as I can remember these are the classes I added:
_a.ss01: a' a.ss01 aacute.ss01 acircumflex.ss01 adieresis.ss01 agrave.ss01 aring.ss01 atilde.ss01
_i: i' iacute icircumflex idieresis igrave imacron iogonek iring dotlessi
_y: y' yacute ycircumflex ydieresis ygrave
_period: period' comma colon semicolon ellipsis
_question: question' question.ss03
_copy: copyright' registered
Is there a typo somewhere or am I doing something wrong? How can I check which glyphs are supposedly missing from the font?

