Synchronous Version Switching

Hello all:
I'm using chrony version 4.1 on an embedded Linux system；127.0.0.1 cannot be synchronized in version 4.1, but it can be synchronized in version 3.5. Is this a difference? The following is my configuration file and the firewall is disabled.
server 127.0.0.1 iburst minpoll 3 maxpoll 3
driftfile /var/lib/chrony/drift
makestep 1.0 3
rtcsync
allow all
local stratum 10
logdir /var/log/chrony

Start the chronyd service：
[cid:[email protected]]
执行chronyc sources Ca Cv:
[cid:[email protected]]