You should use two-factor authentication with every digital service that supports it.
We use Google Apps at Convivio. You must ensure your Convivio Google account is secured with 2FA.
Sign in to your Convivio Google Apps account
You should turn on 2FA on your Slack account also.
In Slack, click on your name under the 'Convivio' Slack organisation name at the top-right and select 'Profile & Account'
Click on the three-dots button on your profile in the sidebar and select 'Open account settings', which should take you to https://weareconvivio.slack.com/account/settings
'Two-Factor Authentication' is the second item in the central panel. Click 'Expand' and follow the instructions to activate 2FA.
If you are not using your Convivio Google Apps account for single sign-on and authentication then here are some other tools, services and accounts on which you should enable 2FA: