Crossref plugin not working

The Crossref plugin not working in a single journal features 500 error in the page in the access the option data export in the link DOI manager. My version is OJS


In your PHP error log, you will find details on the PHP error which will describe what triggered the HTTP 500 response. Please share that message here.

This is my log error:

[Tue Apr 23 14:06:15.781289 2019] [fcgid:warn] [pid 5683] (32)Broken pipe: mod_fcgid: ap_pass_brigade failed in handle_request_ipc function
[Tue Apr 23 14:06:27.070160 2019] [fcgid:warn] [pid 6865] mod_fcgid: stderr: NOTICE: Undefined offset: 10 (/plugins/importexport/crossref/classes/, referer: /manager/importexport/plugin/CrossRefExportPlugin
[Tue Apr 23 14:06:27.070279 2019] [fcgid:warn] [pid 6865] mod_fcgid: stderr: PHP Fatal error: Call to a member function getPublished() on null in /plugins/importexport/crossref/classes/ on line 549, referer: /manager/importexport/plugin/CrossRefExportPlugin

This error message seems to be the same as the error you describe here:

Is the the same journal or a different journal which exhibits this problem?

yes, the same journal.

Did you resolve the negative assoc_id values mentioned in the previous thread?

Yes, i removed the entries, but the problem persists.

Are there new results that match the earlier SQL query of:

SELECT pa.* FROM published_articles pa LEFT JOIN issues i ON (i.issue_id = pa.issue_id) LEFT JOIN articles a ON pa.article_id = a.article_id WHERE (pa.date_published IS NOT NULL OR a.status = 3) AND i.issue_id IS NULL;


not there are results.