What's happening?
LinkedIn Sales Navigator is enabled for Leads, Contacts, Opportunities, and Accounts, but the feature is not visible on Accounts & Contacts forms.
Reason:
The LinkedIn Sales Navigator control was not added to the custom form being used.
Resolution:
To resolve this, manually add the LinkedIn Sales Navigator control to the custom form by following the instructions provided in the article: Add LinkedIn Sales Navigator controls to Dynamics 365 forms | Microsoft Learn