Howto bind BGP to single interface?

Trying to determine what is wrong with "strict bind yes;" under "protocol bgp". The docs suggest that my syntax is correct. protocol bgp vultr { local as 1234; source address 111.22.33.44; # strict bind yes; # Fails if uncommented import filter accept_all; export filter export_bgp; # import none; graceful restart on; multihop 2; neighbor 11.22.33.44 as 11111; password "xxxxxxxxxxxxxxxx"; }