From the Admin console Home page, go to Security >>Less secure apps.
To apply the setting to everyone, leave the top organizational unit selected. Otherwise, select a child organizational unit or a configuration group.
Select the setting for less secure apps:
Disable access to less secure apps (Recommended):
Users can’t turn on access to less secure apps.
When you disable access to less secure apps while a less secure app has an open connection with a user account, the app will time out when it tries to refresh the connection. Timeout periods vary per app.
Allow users to manage their access to less secure apps:
Users can turn on or turn off access to less secure apps.
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