Please check the Agent core.log to verify the error.
<Informatica Cloud Secure Agent>\apps\agentcore\agentcore.log .
Can you also verify that you started the agent as "Admin". You may want to try "Running as Admin".
Please verify following:
1.the user running agent service must either a part of performance monitor group (non-admin group) or admin group.
2. verify the user running the service has full access to the secure agent installation directory.
Addtional note- how to check which user running agent service- go to Service.msc > Informatica Cloud Secure Agent > right click on the service and go to property > login as.
This may be due to permission issues. Check if you have required permissions as 'Administrator'.
You may understand the issue form 'agentcore.log' (**\Secure Agent Directory\apps\agentcore\agentcore.log)
If you still face issue, kindly contact Informatica support for further investigation.