Android mobile app certificate verification fails

I got the android mobile wallet application up and running and I’m running blockcert with bicoin testnet.
I couldn;t get the cert verified from the mobile app. I updated the blockchain service URL to testnet and i don;t find any document to explain whats the base URL for. Could you please explain what this URL actually does? Does it looks for any files specifically from this URL to verify the cert like issuer json and blockchain cert?

public static final String BASE_URL = “”;

public static final String BLOCKCHAIN_SERVICE_URL = “”;