I have seen this has been posted before but but cannot find a definitive answer.
When trying to add a new integration
(System > Integrations > Add New Integration), the New Integration page comes up but with nothing on it except Save and Back buttons. Clicking the Save button results in
Notice: Undefined index: all_resources in /vendor/magento/module-integration/Controller/Adminhtml/Integration.php on line 141
Magento version is 2.2.6
I have tried flushing the cache and re-indexing. And I have the same problem on both the production site and staging site (default mode).
Much appreciated if anyone can help with this.