You need to have installed Ebsta into Chrome and connected it to your Salesforce account. If you haven't already done this, please refer to this article:
Connect your Gmail mailbox to Ebsta
1. In Gmail, click the Ebsta button in the top right-hand corner to open the Ebsta set up window.
2. Click Connect your Google Account to Ebsta.
3. Sign in to your Gmail Account with your username and password.
4. Give Ebsta permission to connect your account by clicking Allow.
5. Your mailbox will now be connected to Ebsta.
Note: You can connect additional mailboxes that you may have by logging into your other Google accounts and repeating this process.