"Psych::DisallowedClass" error fix

These changes are already included in Redmine 5.0.3. We recommend you use version 5.0.3 and above. Also, if you have a problem with an error, add class XXX (example 'Date') to the exceptions, then please write us so that we can make full corrections.

This fix is related to the new Hash serialization. The error itself looks like this:

Completed 500 Internal Server Error in 129ms (ActiveRecord: 22.2ms)
Psych::DisallowedClass (Tried to load unspecified class: ActionController::Parameters):

And it is related to:

For the plugin to work correctly, you need to make changes in the following file of the Redmine itself. Please open config/application.rb. Go to line 35. Add into:


the following line


Don't forget to add a comma above. It looks like this:

    config.active_record.yaml_column_permitted_classes = [

Save change. Restart your Redmine.

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