Error is seen when trying to edit the password of a Workflow Credential saved on the Gallery:
Credentials could not be updated
Invalid Username or Password
This is a known defect that is being reviewed by Alteryx.The update is getting a POST error 405 methods not allowed when trying to use the request URL http://mygallery/gallery/api/credential/xxx.
The client can delete the user credential and re-add it, with the updated password.
When a client deletes and adds a new credentials will existing scheduled workflows use the new credential ... or do they have to republish them all?
I notice that the URL to the new credential is quite specific.
It looks like you will need to republish all of the workflows.
Not sure if there's a fast way to do this or not.
edit: Also looks like you need to reenable all of the schedules, if the workflows were scheduled.