Subtable Overflow in lookup: 2 type: MarkToBaseAttachement

Hi all, I’m trying to generate a Variable Font, but I keep getting a Problem compiling GPOS table. I have removed all of my non-standard anchor names but that didn’t solve the issue. Does anyone know what “2 type” is?

Do you have a lot of kerning pairs?

Add a custom parameter in Font Info > Font: Use Extension Kerning.

oh yeah that fixed it. Thanks so much!