Looks like the URL is wrong.
Check if you have something like http://test.com/deeplink/UserNTID=value, if yes, this is not a proper URL.
You must have something like http://test.com/deeplink?UserNTID=value or http://test.com/deeplink/UserNTID/value
Read for more details: https://docs.mendix.com/appstore/modules/deep-link
Based upon the option you are using, you might enable or disable few booleans in the Deeplink entity
Perhaps you need to URL encode the parameter that you’re passing into the deeplink?