Hi Yaron,
I found the problem. We have SSL decryption in our firewall and it has been implemented recently. This explains why Cloud Manager was working before.
SSL decryption requires the host -- in this case Cloud Manager linux host -- to have the trust certificate installed (.crt file).
Although the trust certificate has been installed, Cloud Manager still prompt me "proxy error". So it looks like Cloud Manager software cannot tolerate SSL decryption.
So for now, I have disabled SSL decryption and now Cloud Manager is back to normal.
I can perform SSL decryption exclusion, however, I need to have the list URL that Cloud Manager is using. If you have the list of URL, that would be great.
Thanks.
Wilfred