Found good advice about your case:
Also see this part of man ovs-dpctl:
This program works only with datapaths that are implemented outside of
ovs-vswitchd itself, such as the Linux and Windows kernel-based data‐
paths. To manage datapaths that are integrated into ovs-vswitchd, such
as the userspace (netdev) datapath, use ovs-appctl(8) to invoke the
dpctl/* commands, which are documented in ovs-vswitchd(8).
Also you may try to use this tool to see flows:
dump-flows switch [flows]
Prints to the console all flow entries in switch's tables that
match flows. If flows is omitted, all flows in the switch are
retrieved. See Flow Syntax, below, for the syntax of flows.
The output format is described in Table Entry Output.
By default, ovs-ofctl prints flow entries in the same order that
the switch sends them, which is unlikely to be intuitive or con‐
sistent. Use --sort and --rsort to control display order. The
--names/--no-names and --stats/--no-stats options also affect
output formatting. See the descriptions of these options, under
OPTIONS below, for more information