Thank you for posting your query on Microsoft Q&A, from above description I could get that you have 2 following queries regarding power apps and Entra ID license and integration on support w.r.t Entra ID.
Please do correct me if there is any discrepancy in my understanding:
Who is responsible for the support of the Microsoft AD in case there are post implementation issues that arise between Azure AD and Okta?
For any issues related to features of Entra ID, you need to work with Microsoft support. However if problem is narrowed down to the IDP i.e., Okta, then you need to engage with Okta support.
In addition we are wondering if Microsoft licenses(Microsoft power apps per user plan or Microsoft power apps per app plan) would cover the Okta-Azure AD connection support or do we need to buy additional support plans available?
Microsoft support would be able to assist only for Entra features and not for the any Okta component not working during or post integration due to knowledge gap.
The free edition of Microsoft Entra ID is included with a subscription of a commercial online service such as Microsoft Azure, Microsoft Dynamics 365, Microsoft Intune, Microsoft Power Platform,
Support is available online and by phone for Microsoft Azure paid and trial subscriptions on global technical, pre-sales, billing, and subscription issues. Phone support and online billing support are available in additional languages.
Explore the range of Azure support options and choose the plan that best fits your scenario, whether you're an IT admin managing your organization's tenant, a developer just starting your cloud journey, or a large organization deploying business-critical, strategic applications. Azure customers can create and manage support requests in the Azure portal.
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