Anveo does not block pings.
$ ping sip.ca.anveo.com
PING sip.ca.anveo.com (67.212.84.21) 56(84) bytes of data.
64 bytes from 67.212.84.21: icmp_seq=1 ttl=46 time=93.9 ms
64 bytes from 67.212.84.21: icmp_seq=2 ttl=46 time=92.9 ms
64 bytes from 67.212.84.21: icmp_seq=3 ttl=46 time=93.4 ms
64 bytes from 67.212.84.21: icmp_seq=4 ttl=46 time=91.9 ms
64 bytes from 67.212.84.21: icmp_seq=5 ttl=46 time=91.6 ms
64 bytes from 67.212.84.21: icmp_seq=6 ttl=46 time=94.5 ms
64 bytes from 67.212.84.21: icmp_seq=7 ttl=46 time=92.0 ms
64 bytes from 67.212.84.21: icmp_seq=8 ttl=46 time=92.4 ms
64 bytes from 67.212.84.21: icmp_seq=9 ttl=46 time=92.5 ms
64 bytes from 67.212.84.21: icmp_seq=10 ttl=46 time=92.1 ms
--- sip.ca.anveo.com ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 9009ms
rtt min/avg/max/mdev = 91.693/92.772/94.576/0.919 ms
$ ping sip.anveo.com
PING sip.anveo.com (72.9.149.69) 56(84) bytes of data.
64 bytes from 69.prd1.tms.anveo.com (72.9.149.69): icmp_seq=1 ttl=54 time=50.2 ms
64 bytes from 69.prd1.tms.anveo.com (72.9.149.69): icmp_seq=2 ttl=54 time=50.2 ms
64 bytes from 69.prd1.tms.anveo.com (72.9.149.69): icmp_seq=3 ttl=54 time=50.5 ms
64 bytes from 69.prd1.tms.anveo.com (72.9.149.69): icmp_seq=4 ttl=54 time=50.5 ms
64 bytes from 69.prd1.tms.anveo.com (72.9.149.69): icmp_seq=5 ttl=54 time=50.7 ms
64 bytes from 69.prd1.tms.anveo.com (72.9.149.69): icmp_seq=6 ttl=54 time=51.4 ms
64 bytes from 69.prd1.tms.anveo.com (72.9.149.69): icmp_seq=7 ttl=54 time=50.4 ms
64 bytes from 69.prd1.tms.anveo.com (72.9.149.69): icmp_seq=8 ttl=54 time=50.3 ms
64 bytes from 69.prd1.tms.anveo.com (72.9.149.69): icmp_seq=9 ttl=54 time=50.4 ms
64 bytes from 69.prd1.tms.anveo.com (72.9.149.69): icmp_seq=10 ttl=54 time=50.1 ms
--- sip.anveo.com ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 9011ms
rtt min/avg/max/mdev = 50.174/50.530/51.413/0.451 ms
If you're not getting a response then they or your route to them is down.
Anveo does route calls to their other datacenters if one goes down, so that might be why incoming is still working.
/M