1- Have you looked on the device to see if any errors in the log?
2- Have you looked in the device.daemon error log file to see any errors there?
3- Have you tried to add the device as unreachable and then let the device connect in to the NSM?
4- What device and O/S version are you having the problem with?
5- Did you do anything to the device since the initial add in terms of O/S upgrade?
1. no errors
2. on the NSM?
3. no, I just tried to add it exactly the way I added it the first time, but it hangs on the SSH key
4. it won't add anything anymore, it hangs in the same spot. I'm trying to add EX4200's, but I just removed an ssg5 and it won't re-add that one either
5. I upgraded the EX4200's JunOS version, but the SSG5 I did absolutely nothing to it, I simply removed it and tried to re-add it just to see if I could.