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Conga Support

MIME types not supported with Salesforce


You might see the following error if Enable Content Sniffing protection is selected under the Content Sniffing protection section in Salesforce Setup: Refused to execute script from '' because its MIME type ('text/plain') is not executable, and strict MIME type checking is enabled.


When a user creates a Conga Grid custom action, a custom MIME type is automatically associated with it which is not supported in Salesforce security because the MIME type is not standard.

If a custom action is not showing under the actions menu even when it has been enabled in Conga Grid Setup, review your developer console:

Chrome - Chrome Menu -> More Tools -> Developer Tools -> Console or hit the F12 key
FireFox - FireFox Menu -> Developer -> Browser Console or hit Ctrl + Shift + k
Edge and IE - Edge/IE Menu -> F12 Developer Tools or hit the F12 key


To fix the issue, go into Salesforce and select Setup -> Security Controls -> Session Settings and then uncheck the Enable Content Sniffing protection checkbox under the Content Sniffing protection section.