You are receiving an error message similar to the one shown in the image below when creating an app with "_" in the name.
Solution
When creating an application, MindSphere will not accept a URL with an underscore in its name. Instead, we would advise you to use a "-" in replace of any "_" for an app name created within Cloud Foundry.
For further information on the Cloud Foundry, please visit the link below:
https://developer.mindsphere.io/paas/index.html
Notes