Hi
You’re not using SRV records and that may be the root cause of your issue.
Please try something like this:
backend tsdb_backend_query
server-template tsdb_query 5
_mfm-monitor-opentsdb._tcp.service.mfmconsul:4242 check resolvers dns
inter 1000
if “mfm-monitor-opentsdb” is your service name in consul.