OK.
First of all I do not recommend people ever use the Utility menu to delete changes that for whatever reason fail. You need to fix them, which means learning why they failed and being able to interpret what OPS is telling you so you can fix them. If you've been in the habit of deleting changes then your SX2000 tel directory is likely considerably out of synch with the directory in Ops Man. Anyway, enough about that for right now. That's not your problem.
Lets try some troubleshooting;
From the main screen in OPSMan go to the Utilities tab (on top, next to Help) and then click on Manage, then click on the SX2000 system you're after and then click on the Launch button. What happens? Can you get logged in to a Maintenance session on the SX2000 via this method? Yes or no.
If you can, then we have connectivity between OPS and the PBX so go ahead and close this window.
But If not... then close this window and click on configuration then scroll down to highlight Network Elements then scroll down and click on the editor. When this screen opens click on either next or previous until you see the name of the Element Name appear in the first window (it will be greyed-out, not to worry).
When you have the right Element name found then click on the settings button. That will give you at least 1 and likely two IP addresses. Write them down. Don't change them.
Now close out of everything we just opened, all the way back to the main OPSMAN window
Use your mouse to click on Start, then click on Run. Inside the "run" box enter the letters CMD and then press the "enter" key. This should open up a black command window and your cursor should be blinking at the end of a short line of text that tells you what subdirectory or folder you're in. This is just info, not important. ANyway, type in the command PING followed by a space and then followed by one of the IP addresses you wrote down above, example, PING 10.192.218.10 followed by the "enter" key. You should see some replies. Do you?
Does the reply say Destination Host Unreachable ??
If it does then you have a problem with your network or connectivity between your network and the PBX.
If you see replies with the word "bytes" and the line ends with something likt TTL=xx then we're able to PING the PBX and we're OK.
Lets stop here for now.