OS server not going online

I am having a very strange problem. I have a pair of redundant servers both the servers were working fine when suddenly the Master server stopped working. I tried bringing it online but couldnt. So i did entire compile with memory reset. I have done all the necessary steps. I have compiled the OS, configured the server, downloaded the project to server, downloaded netpro connections, simatic shell is showing all the PC's, Station configurator is showing WinCC connection healthy. I cannot find another step that I am missing.I checked in ES it goes online. The only difference is I did not do enitre compile with memory reset in ES. Does this effect the communication between OS server WinCC and PLC?? After I did entire compile in server my other server also stopped communicating. Please help me because of this my clients are not communicating and I am in middle of commisioning.

Thank you.

did you make any changes in the netpro? try compile the netpro once and download the connections to the servers afresh(delete the existing ones and restart the pc's too befor the new download). Also whatif you do full compile withmemory reset in the ES too? are the communications becoming unhealthy in the ES in that case?