OTM UI is giving 502 error on first launch

Hello,

I have installed required softwares and OTM on VMWare Linux 64 bit virtual machine. After installation when I am trying to launch OTM UI, it is loading for sometime and giving 502 error message as Proxy Error, invalid response from proxy or gateway.

Need help on this. Is there an issue with firewall? or any memory issue. because I have allocated 4GB of RAM only. loading for 5 mins and giving 502 error.

Thanks in Advance...

Regards,
Rajasekhar