Emails not arriving while activities show.
After the Summer 24 release, Salesforce has enforced the email verification for all the users in the org. If any user email is not verified then those users outbound emails will be impacted!
If you visit “personal setting and advanced user details page” and you see “Verify” next to the email address of the User then this User cannot send any emails:
Click on the link received in verification email and the User is all set!
More information on this update can be found here:Â Verify Email Addresses to Meet the Email Verification Requirement