this has me stumped, and wondering if anyone else has encountered it.

I have a profile search results page where the result table includes both standard fields and custom fields.

I am able to sort the table successfully on the standard fields by clicking the arrows/column headers, but the custom fields column sort fails. I see one of two errors:

  1. If I click the up/down arrows next to the column header text, a popup "Network Error Unable to reach the server. Please refresh this page in your browser and try again." appears, and a 500 server error is registered in the web server error log.

  2. If I click the column header text, I get a 404 page with the error message "Class name must be a valid object or a string"

You can see this in action live at https://www.fawco.org/index.php?option=com_civicrm&task=civicrm/profile&force=1&gid=18&reset=1&crmRowCount=100&Itemid=388 ("Name" and "Country" are default fields, "FAWCO Region" is a custom field.)

Per my testing:

  • Search itself works properly.
  • There are no errors in the CiviCRM log or the Joomla log.
  • Joomla and CiviCRM debug modes have not shown any errors.
  • web server logs report as described above, 500 for the sort request via arrow, 404 for the sort request via text.
  • Adding and removing different default and custom fields to the results makes no difference: default columns consistently work and custom consistently fail.

System is Joomla 3.9.10 with CiviCRM 5.15.1.

Has anyone seen this before, or could someone give me a hint where I could start troubleshooting?

  • Further investigation: monitoring the network traffic, it's this custom field sort request that is failing: fawco.org/index.php?option=com_civicrm&task=civicrm/… But the exact same format request for the standard data field sort is successful. I just have no idea where to start looking for the difference in behavior.
    – minbori
    Oct 2, 2019 at 11:30
  • Look in the apache error logs. It should give some info about the code file and line number where the "Class name must be a valid object or a string" error is happening.
    – Demerit
    Oct 2, 2019 at 13:16
  • There is no event in the Apache error logs. Am trying to test whether PHP errors are actually being logged.
    – minbori
    Oct 4, 2019 at 11:34
  • 1
    OK, so here's the error: [04-Oct-2019 15:53:43 UTC] PHP Fatal error: Class name must be a valid object or a string in /home/fawcoho/public_html/administrator/components/com_civicrm/civicrm/CRM/Contact/BAO/Query.php on line 6373
    – minbori
    Oct 4, 2019 at 16:02
  • Now I'm really not sure where to go next -- this is out-of-the-box CiviCRM code, nothing custom.
    – minbori
    Oct 4, 2019 at 16:33

1 Answer 1


For 5.15.1 you can add these lines just before line 6373 in CRM/Contact/BAO/Query.php.

if (empty($fieldSpec['bao'])) {

There will also be a similar workaround put into 5.18.2 when it is released. https://github.com/civicrm/civicrm-core/pull/15454

  • Thanks, that worked! I also installed 5.18.2 today and the problem is gone.
    – minbori
    Oct 9, 2019 at 11:41

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