QuickBooks multi-user mode not working on 2 of my systems. Help me out.

So I opened my company file today and I ran into a problem, Quickbooks-multi-user-mode-not-working. I have 3 systems that are supposed to access my QB company file but only one of them is able to function. Initially, I thought the problem was on Intuit’s end and their server was down but now I feel it’s my own system. I don’t really know what happened all of a sudden, I mean, everything was working fine till last night. Do you people have any solution to this problem or any idea what I should do next? If any of you have faced the same problem, please help me out.

Internet link disabled by moderator.