tyring out proxy ping

so after installing i try proxy ping setting my router's ip address, either one of two snmp RW communities, and a destination ip. simple enough it seems, but i get the following two errors depending on what community i try:
E2001: No response to SNMP queries - [router ip]
E1001: Unknown host - [router ip]

now granted, i'm a noob, so i'm probably missing something here. i know i have access to the router from this pc because i can access it via ssh or telnet without issues. i've installed oputils on this very pc, so i'm accessing it locally.

another thing that i noticed is there's no option to specify a vrf for a multi vrf-capable router, so using this tool is not as useful to me atm. it would be a nice feature, or i just haven't looked thouroughly enough.