some NEs not appeare in the main topology

Currently, you are not using user "admin" login to the NMS 

If the admin account cannot view the device, the device may be in another subnet. In this case, use the solution provided by me. For other accounts, perform the following steps:

1, Confirm your account belong to which "user groups"

2, check you user group can operation which domain of "object set"

3, check the object set members.

4, followed the operation guide add the NEs 

Thanks!

Hi,
I think you mean users who have administrator level , not admin user , because admin user has all operation rights .
- if you have user with administrator level you should ask the authrised person to add the NEs to your controled domain .
Regards