Here are the steps, for anyone confused about how how to change a Moodle using SendGrid for outgoing email, to one using SendGrid API -- as SendGrid is requiring you to do now (October 2020).
- Sign in to your sendgrid.com account.
- In the left column, click on Email API, then Integration Guide
- In the page labeled "Integrate using our web..." choose SMTP Relay
- Click Create API Key, then SAVE IT! -- it will disappear after you read it.
- Leave this page open, you will return to it in a minute.
- In another browser tab, log in to your Moodle, go to Site Administration/Server/Outgoing mail configuration
- Set it up like this:
SMTP hosts: sendgrid.net:587
SMTP Security: TLS
SMTP Auth Type: LOGIN
SMTP username [yes, enter "apikey" as your username]: apikey
SMTP password: HERE ENTER THE API KEY YOU JUST GENERATED ON SENDGRID AND COPIED
- At the bottom of the page, click Save Changes.
- Return to SendGrid.com, check the box that you have updated your settings, then click "Next Verify Integration."
- Follow the steps for verifying that this email setting works.
- Still on SendGrid.com, open your Account and set up two-factor authentication, which they now require. DO NOT DO THIS UNTIL AFTER YOU HAVE INSTALLED THE API KEY in your Moodle. Then sign out of SendGrid and verify that the two-factor authentication works.
You might want to force Moodle to send another email, to be doubly sure the emails are working.
You can do this by going to the Moodle login and checking "Forgotten your password." That should send you an email from the Moodle you just updated. If you do not see this email, be sure to check your email client's Spam and Trash folders.
I hope this includes everything, for those of us who are easily confused.