getting syslog message "Next-hop resolution requests from interface <id> throttled" on my MX-104 with Junos 14.2R7
Typically this happens when someone sends loads of packets destined to a non-existing IP on the interface.
MX ge-0/0/0.0 has IP 203.0.113.1/24
There are 2 actual hosts behind ge-0/0/0.0 : 203.0.113.2 and 203.0.113.3, the rest of IPs are unused.
You announce the 203.0.113.0/24 route to the rest of Your network and internet.
Someone sends packets ate high rate with dst.IP == 203.0.113.77 and src.IP=198.51.100.79
Your MX throttles the ARP requests that are coming out of ge-0/0/0.0 and are not answered - because there is no host 203.0.113.77 in existence!
As Alex mentioned above these are requests for non-existence IPs. These messages shouldn't be a problem and is not expected to cause any service impact.