Make sure you complete all the steps from the same Google Account and you always use the same email address.
To check the email address, go to your Google Play Developer Console and click on Developer Account > Account details. This should be the same one that you logged in with.
Send Google Invitation
Creation of the service account and JSON file
Furthermore, it is necessary to create a so-called service account to set access rights and generate a JSON file.
Log into the Google Play Console and click on Settings > API access and then on the Create service account button.
In the window that now appears, click on the link to go to the Google API Console. Do NOT click on DONE!
In the Google API Console, click on + Create Service Account.
Now follow these three steps:
a. Specify the name of the service account
You can enter appyourself here. The name will only be visible in your console. You also have the option to add a description of the service account. Now click on the Create button.
b. Select roles
You select the role Service Account User, which you can find under Service Accounts. Then confirm with Continue.
c. Provide JSON key
Now you need the JSON key. Click on Provide JSON key and then on the Create Key button (make sure that JSON is selected under Key type). Then the JSON file is generated and saved on your computer. Click the Close button and then Done.
Go back to the previous website and click on Done in the Create Service Account pop-up window.
You are now in API access, where you allow access to the newly created service account (by clicking Grant Access).
You can now add new users by clicking on the corresponding button.
After you have followed all these steps, you now need to send us the JSON file that you have generated during the process.
You should find the JSON file within the Downloads folder on your device. The file has the ending .json.
Finally, upload the File together with the other data of your Google Developer account in Fitogram under Branded App => Publish => Android.
Note: The creation of the JSON file is best done on Google Chrome or Mozilla Firefox Browser.