To see which application you have authorized to read email, use Security Checkup for Gmail.
Step 1 : Log in to your Gmail account, go to Settings and find Apps with Account Access under Sign-in and Security.
Find a list of licensed applications
Step 2 : Click Manage Apps to open the list of applications linked to Google.
Open the list connected to Google Gmail
Step 3 : At the list above, select Remove Access to remove the previously granted rights.
Removing Gmail access has been given to 3rd party applications
To ensure the safety of your information, think carefully before empowering 3rd party applications.
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