Hello! I’ve read most of the other posts on this topic, but none of them helped me.
If I export my glyph file to a ttf (or otf) and then open this ttf again in Glyphs, the kerning is not displayed for a certain group. In addition, the kerning is not displayed in the font selection in Illustrator, but it is displayed correctly in the text field of Illustrator (when typing). However, most of the other kerning groups have been exported correctly and are displayed.
That is not a good way to test a font. You can reverse engineer compiled font files only to a certain degree. If you want to examine the opentype font file, better use apps like OTMaster or FontTableViewer.
For kerning, I recommend to only test in a real life environment. Best in a browser. In Adobe apps, make sure metric kerning is selected, and move your cursor in between letters to see the value displayed in the Character palette.
I assume the Adobe font menu preview disables kerning.
Are you really using kerning to achieve the connections? If so, consider deleting the kerning you have now, and starting from scratch with spacing. Your font should (more or less) work without kerning. If the glyphs are that far apart without kerning, then the spacing can be improved.