Cannot export variable for testing

I cannot export the variable font, I’m getting this message


Unfortunately, I’m not allowed to share the typeface.
Any Idea where to look for the issues?

Lookup index 4 appears to be pretty large. Could be the bulk of the kerning…?

When exporting a variable font, all the GPOS will get some additional data that will increase the table size and cause an overflow when the single instance export would be fine.

Could you send me that file for testing?