It's not a built-in function, so one of your administrators has disabled or removed the add-on providing it.
If you are on Cloud, that would be consistent with Atlassian's gradual removal of some of the standard add-ons they're trying to get rid of (Misc Extensions, JIRA Suite, Toolkit etc)
Hi Atlassian community, My name is Max and I work on the product integration team at Atlassian. I am pleased to announce the early access program for the Jira Cloud add-in for Outlook. This add-in...
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