Vidya Sudharshana Thank you for posting this question in Microsoft Q&A. It is not possible for users to manually restart APIM service/instances as described in other thread.
Sorry to hear that you are facing issues with APIM service. Do you still see the status as
Stopped in Overview page of APIM instance in azure portal? If so, I suggest you open a ticket to our support team to investigate and mitigate this issue as quickly as possible.
Do you have a support plan with us? If not, I can assist you in creating one-time free technical support for you. Let me know your thoughts.
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