In DIVI theme, new-post and post-edit pages return Page not Found Error

All of a sudden, after activating DIVI theme for a new sub-site, new-post and post-edit pages return Page not Found Error.
If I switch theme, edit function works. DIVI theme edit-post and new-post works without any error on existing DIVI sites. Only new DIVI sites are affected, which is strange, since there is only one core DIVI theme (multisite)