please help me!!! Can't bind zserv socket on 0.0.0.0:2600: Permission denied

[difficultwork]

when I started zebra with opt '-z 0.0.0.0:2600' in alpine container, it failed with this information:

ZEBRA: [EC 100663299] Can't bind zserv socket on 0.0.0.0:2600: Permission denied

my linux kernel version is 2.34.0.
alpine linux version is 3.14.
frr version is 7.5.1.

I set cap for zebra, but has the same problem.

/ # getcap /usr/lib/frr/zebra
/usr/lib/frr/zebra cap_net_bind_service,cap_net_admin,cap_net_raw,cap_sys_admin=eip

please help me. thanks