Setup Sendgrid

If you verify only a single sender in Sendgrid, you can only send from that email address. Other email addresses will not be accepted unless you verify your domain.

Go to sendgrid.com and register for a free account. Then, navigate to Settings > API Keys and Create a new API Key.

Create an API Key with the settings you need. Full Access is usually enough.

Then, back in your Bubble editor, navigate to Plugins > API Connector > Sendgrid and enter the API key you just generated in the Authorization header. Make sure it's preceded by 'Bearer'.