I cannot view Activities on a Contact's Activities Tab, or my activities on my CiviCRM Dashboard. In both cases I receive the following error:

DataTables warning: table id=DataTables_Table_0 - Invalid JSON response. For more information about this error, please see http://datatables.net/tn/1

I am using CiviCRM 4.7.28 in Wordpress 4.9.1. I have the following Extensions active in CiviCRM:

  • iATS Payments 1.6.1
  • Summary Fields v. 3.1.1
  • Extended Report v. 3.0
  • Displays relationships in the contact summary v. 1.2
  • Mailchimp v. 2.0.1

1 Answer 1


In order to fix this regression, you need to apply this tiny patch, which wasn't merged in time for the 4.7.28 release.

Cheers, Olivier;

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