Chrony NTP: synchronization with an external NTP server in my Docker container works for a few seconds, but after that, synchronization stops working

Time synchronization with an external NTP server in my Docker container works for a few seconds, but after that, synchronization stops working : logs : 2024-09-08T20:54:15Z chronyd version 4.0 starting (+CMDMON +NTP +REFCLOCK +RTC +PRIVDROP +SCFILTER +SIGND +ASYNCDNS +NTS +SECHASH +IPV6 -DEBUG) 2024-09-08T20:54:15Z Initial frequency 83333.333 ppm 2024-09-08T20:54:15Z Using right/UTC timezone to obtain leap second data *2024-09-08T20:54:20Z Selected source 196.200.160.123 (2.debian.pool.ntp.org)* 2024-09-08T20:54:20Z System clock wrong by -5318.299142 seconds 2024-09-08T19:25:41Z System clock was stepped by -5318.299142 seconds 2024-09-08T19:25:41Z System clock TAI offset set to 37 seconds 2024-09-08T20:54:45Z Forward time jump detected! **2024-09-08T20:54:45Z Can't synchronise: no selectable sources** /etc/chrony/chrony.conf file : confdir /etc/chrony/conf.d pool 2.debian.pool.ntp.org iburst sourcedir /run/chrony-dhcp sourcedir /etc/chrony/sources.d keyfile /etc/chrony/chrony.keys driftfile /var/lib/chrony/chrony.drift ntsdumpdir /var/lib/chrony logdir /var/log/chrony maxupdateskew 100.0 rtcsync makestep 1 3 leapsectz right/UTC