To ensure that you can access the Securly admin console without errors, it is essential to add Securly as an Application to your API control in G Suite.
To do this, you will need to log in to your Google Admin console and navigate to Security > API controls and click on the 'MANAGE THIRD-PARTY APP ACCESS'.
Now select 'OAuth App Name or Client ID' from the dropdown for 'Add app'.
Search for 'Securly' and select the radio button for 'Securly' from the list displayed.
Click on 'ADD' and you are done.