[ojs/plugins/importexport/crossref/] HTTP ERROR 500

I have upgraded ojs 2.4.8 to 3.0.2 but there is some problem, So I restore to ojs 2.4.8. and there is some issue about table, but I can solve it. And now there is problem in system plugin. I have google it, and have some recomendation:

  1. installed curl
  2. disable all plugins
  3. check error, I checked it, got error ata crossref, but have no idea about it.

Can anyone suggest me other option?


I have solve this by remove file ojs 3.0.1. thanks