@Nidhi Priya, Thanks for posting in Q&A. To deploy iOS LOB app, please ensure you have joined iOS Developer Enterprise Program. And the in-house app is built with an included provisioning profile and code that is signed with a certificate provided by Apple. Please confirm on this. If all are met but still not working, you can open case to get help on it.
https://learn.microsoft.com/en-us/mem/get-support
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.