Good morning Nghia,
First, are you sure the PVP7 and L35E are on the same physical network and same subnet?
To be sure, with a PC plugged into that network, try to ping both the PVP and PLC. Or open RSWho in RSLinx Classic to insure both show up.
Now verify the IP addresses, subnet masks, and default gateways are all correct.
With connectivity out of the way, be sure your shortcut for the CompactLogix L35E has been added correctly.
With older CompactLogix, i.e. those prior to the 5370 (L1, L2, L3) and 5380, the shortcut had to point to the actual controller, which is nested under a Controller Ethernet Card and backplane, as I discuss in Lesson 22 at the 5:52 mark.
This is important – the shortcut for a L35E will not work if it is pointing to the L35E's Ethernet Card instead of it's controller – this is something that changed with the new 5370 and 5380.
Hope this helps,
Instructor at The Automation School