Hazelcast apparently is installed but doesn't show on plugin's page


I’m trying to install Hazelcast on 2 EC2 instances. My Openfire is 3.9.3, and I downloaded hazelcast 3.4 from their official site.

If I try to upload it to my Openfire, it apparently works, returns me to success page, but it doesn’t list on my plugins page, and when I go to /system-clustering.jsp, it shows me that clustering is not available. Other plugins works exactly as expected.

What can be happening? Thanks in advance.