things to check:
1. make sure youve created a keystore and remember all oc its user/passwords.
2. download the android template, and extract the contents in the template folder of Godot located in Local Files "%appdata%"
3. make sure uve also put the correct user/pass in the Project Setting for Abdroid
as well as in Export Settings in Export
4. make sure you have the proper versions of Java and SDK manager tools and API
i had this problem before and one of these was the culprit at some point.