Missed Activity Email Notifications for Microsoft Teams
A very useful feature that users can enable in their MS Teams client is to receive email notifications which will let them know what they have missed when there were away from Teams. Users automatically get actionable missed activity emails which help them to catch up on missed conversations in MS Teams.
The missed activity emails show the latest replies from a conversation, including messages that were sent after the missed message, and users can click Reply to respond directly from within Outlook.
Recent Updates from Microsoft
Starting 13th July 2022, Microsoft has added two new email domains that will be used to send out notifications from Microsoft Teams (emeaemail.teams.microsoft.com and emea.teams.registration.microsoft.com). You might now see these notifications coming from following domains:
How to enable this feature?
Users can enable this feature in Teams client within Settings.
Open Teams Client > Settings > Notifications Tab > Missed Activity Emails

How it looks in Outlook?
Once you enable the setting, for any message in Teams you missed while you are Away or Offline, you will receive an email as below. Note that the actionable messages are not supported in older versions of Outlook and Outlook in Mac. While using unsupported versions, you will still be able to see these email notifications but may not be able to Reply directly from there.
Please refer to https://docs.microsoft.com/en-us/outlook/actionable-messages/ for more details.

You have enabled the setting, still unable to receive email notifications.
One of the reasons for this could be that you have enabled Spam Rules that would prevent these emails reaching your mailboxes.
Starting 13th July 2022, Microsoft has added two new email domains that will be used to send out notifications from Microsoft Teams (emeaemail.teams.microsoft.com and emea.teams.registration.microsoft.com). If you have enabled Spam Rules in your Exchange, please ensure that these domains are whitelisted. You might see these notifications coming from following domains:
email.teams.microsoft.com
emeaemail.teams.microsoft.com
emea.teams.registration.microsoft.com
How "SMTPActionableMessagesEnabled" attribute of command Set-OrganizationConfig affects this setting?
The SmtpActionableMessagesEnabled parameter specifies whether to enable or disable action buttons in email messages. By default, it is set to True. However, admins can disable this parameter. When this parameter is disabled, users will still get email notifications (provided they’ve enabled it in Teams client) but they’ll not be able to Reply directly from Outlook, instead they will see “Reply in Teams”.

References
https://docs.microsoft.com/en-us/outlook/actionable-messages/
https://docs.microsoft.com/en-us/microsoftteams/teams-outlook-email-integration
https://docs.microsoft.com/en-us/powershell/module/exchange/set-organizationconfig?view=exchange-ps