The first step is to open <span class=""><i><b>Firebase console</b></i></span> with your android application and click <span class=""><i><b>Settings</b></i></span>
Click <span class="component"><i><b> Project settings </b></i></span>
Click <span class="component"><i><b> Cloud Messaging </b></i></span>
Copy <b>Legacy server key</b>
Go to your <b>Offito Dashboard</b> and Click <span class=""><i><b>Global</b></i></span>
Click on <b>Notifications</b> gear button
Click <b></b>on <b>Firebase FCM Server Key</b>
Paste your key into <span class=""><i><b>Firebase FCM Server Key</b> field</i></span>
Click <span class="component"><i><b>Save</b></i></span>
That's it. You're done.