To use Maven Tools on an org, your Salesforce user profile has to have the API Enabled flag on under Administrative permissions.
Maven Tools use browser cookies to establish a connection, so make sure Site access is set to automatically allow access to Salesforce domains in the Manage extension Chrome settings.
Browser cookie congestion can also be an issue, it is recommended to clear Salesforce cookies:
Check the console logs:
Sending a recording or a copy of your console logs in support tickets can greatly improve our ability to troubleshoot.
If you are still having issues, contact our support.
If you have API Access Control set to For admin-approved users, limit API access to only allowlisted connected apps you will have to white-list Maven Tools in your org. After Maven Tools tries to establish a connection with your org it will become visible as a connected app. Steps to approve the connected app:
For additional information check Salesforce Help.