question

The extensible tender example requires an access token to configure your merchant account. In order to do so for your app, com.example.user.mycustomtender, you will need to create a Quick Android App via the Sandbox Developer Dashboard (it must be the same package id as you've configured for your custom tender app). Only then will you be able to sideload your App and be able to access to the Clover connectors, TenderConnector in this case.

The reason the example doesn't work right out of the box is due to that token issue as well. I will file a ticket internally to get that fixed.

I am encountering a "500 Access Denied" as well. I performed the following steps: 1) I created the app in my sandbox dev account.
2) Uploaded the APK
3) Opened the web "App Market" from my dev-merchant account and installed my app
4) Opened the "App Market" in my emulator and sync-ed
5) The "App" downloaded automatically
6) Launch the App and click "Initialize Custom Tender"
Output is "500 Access Denied to package com.example.myname.myapp"

I'm also still; getting the same error - anyone here from clover team please help

I am encountering a "500 Access Denied" as well. I performed the following steps: 1) I created the app in my sandbox dev account.
2) Uploaded the APK
3) Opened the web "App Market" from my dev-merchant account and installed my app
4) Opened the "App Market" in my emulator and sync-ed
5) The "App" downloaded automatically
6) Launch the App and click "Initialize Custom Tender"
Output is "500 Access Denied to package com.example.myname.myapp"