When exporting different language(Tamil) to EPUB (for Nook, iBooks, Kobo etc.), the content are not exported, it exports strange characters.
The other exports epub3, mobi, pdf works fine.
Does it work if you open that Epub in Calibre Reader or Microsoft Edge?
Thank you @dac.chartrand. I can read properly on Calibre Reader, but could not read on adobe digital edition. Where is it wrong Epub or adobe edition.
Adobe Digital Editions is very old and doesn’t support all the features of more modern reading systems. If it works in Calibre it should work for your users.