Would you mind trying out the following configuration with your KoBoCollect android app'sGeneral Settings>Server>URL:
Or, configuring your KoBoCollect android app as outlined below:
Regarding your second query:
If you have shared your survey project with enumerators as outlined in the support article Managing Permissions you could configure them differently as outlined above.
Else, an easy approach would be, you upload and deploy your survey project through your admin account and then share the survey project to your data collection account and configure the enumerators KoBoCollect android app with the enumerators account settings.
This helps you maintain data collection in a smooth and easy way also keeping privacy of your admin account.