I installed pressbooks in wordpress multi and pressbook but can’t import epub eBooks so i installed the missing epub validator (apt install epubcheck in Ubuntu 16.04).
If don’t installed the exports because i don’t Need to export.
but when i try to import an epub i still get the error page:
HTTP ERROR 500
when i try to export the epub Check box is even not available to Check also.
I can´t import any epub… i miss something that i did not find yet in documentation.
Can any one Help? Somebody with the same problem?