APEX in ATP errors

Summary

APEX in ATP throws 404 / 500 errors

Content

When I went into the cloud console, Autonomous Database -> Autonomous Database Details -> Tools -> clicked on the "Open Apex" button I just get following errors

 

404

The procedure named f could not be accessed, it may not be declared, or the user executing this request may not have been granted execute privilege on the procedure, or a function specified by security.requestValidationFunction configuration property has prevented access. Check the spelling of the procedure, check that the execute privilege has been granted to the caller and check the configured security.requestValidationFunction function.

 

500 Internal Server Error