So recently at a customer we had the dreaded Not Ready Status under Networking and Security, Installation. Clicking on Resolve does not fix the issue. While this can be several things the most common issue is Update Manager not being available, closely followed by time. Yep, time not being in-sync between vCenter, NSX Manager, SSO, and the ESXi hosts.
However getting the details in the logs will give you a narrowed focus. Whenever you have VIB installation issues always check the host logs and the vCenter logs.
/storage/log/vmware/vpx/eam.log on Linux vCenter
ProgramData/VMware/VMware VirtualCenter/Logs/ on Windows vCenter
To see detailed steps to resolve installation errors see the following VMware KB