Can't upload the latest book (v04) on G••gle Pl•y B••ks for some reason. Is there a way to fix this?

@adevaleev It's a longshot, but if you have calibre, you can try the same thing I do when my Kobo ereader refuses to open an ebook(somehow it recognizes it's not legit); First go to calibre viewer/preferences/miscellaneous and tick the box that says 'keep a copy of annotations/bookmarks...', then open the book with it. It will change it a little(the checksum for the book will be different before vs after). After that, at least those books that my Kobo device refused to open before will now open on it...

@Blanchimont thanks for the suggestion, but that didn't help. I did, however, use Calibre to convert epub ver 3 that I got here into a version 2, which helped.