We recommend installing the app from the marketplace https://marketplace.atlassian.com/apps/1220113/quantify-for-bitbucket.
In order to manually install Quantify for Bitbucket you will need to use the following app URL
Navigate to Bitbucket settings / Installed Apps. Make sure you open it on behalf of the team and not the individual account.
Provide the Quantify for Bitbucket app URL and hit the install button
You will see the permission screen and once authorized app will be installed.
Everything looks good now!