rabbitmq-server fails to start by systemctl start

Question

Versions I'm in:

Ubuntu 20.04.6
rabbitmq-server 3.12.1-1

When I use command systemctl start rabbitmq-server, the server fails to start:

Job for rabbitmq-server.service failed because the control process exited with error code.
See "systemctl status rabbitmq-server.service" and "journalctl -xe" for details.

This is the message from systemctl status rabbitmq-server.service:

● rabbitmq-server.service - RabbitMQ broker
     Loaded: loaded (/lib/systemd/system/rabbitmq-server.service; enabled; vendor preset: enabled)
    Drop-In: /etc/systemd/system/rabbitmq-server.service.d
             └─limits.conf
     Active: activating (auto-restart) (Result: exit-code) since Tue 2023-07-11 15:27:07 CEST; 298ms ago
    Process: 935584 ExecStart=/usr/lib/rabbitmq/bin/rabbitmq-server (code=exited, status=1/FAILURE)
   Main PID: 935584 (code=exited, status=1/FAILURE)
     Status: "Standing by"
kaiyu@kaiyu-Latitude-5500:~

and this is the message from journalctl -xe:

jul 11 15:27:33 kaiyu-Latitude-5500 rabbitmq-server[935767]: 2023-07-11 15:27:33.512944+02:00 [error] <0.236.0>     exception exit: {failed_to_initialize_feature_flags_registry,
jul 11 15:27:33 kaiyu-Latitude-5500 rabbitmq-server[935767]: 2023-07-11 15:27:33.512944+02:00 [error] <0.236.0>                         {rabbit,start,[normal,[]]}}
jul 11 15:27:33 kaiyu-Latitude-5500 rabbitmq-server[935767]: 2023-07-11 15:27:33.512944+02:00 [error] <0.236.0>       in function  application_master:init/4 (application_master.erl, line 142)
jul 11 15:27:33 kaiyu-Latitude-5500 rabbitmq-server[935767]: 2023-07-11 15:27:33.512944+02:00 [error] <0.236.0>     ancestors: [<0.235.0>]
jul 11 15:27:33 kaiyu-Latitude-5500 rabbitmq-server[935767]: 2023-07-11 15:27:33.512944+02:00 [error] <0.236.0>     message_queue_len: 1
jul 11 15:27:33 kaiyu-Latitude-5500 rabbitmq-server[935767]: 2023-07-11 15:27:33.512944+02:00 [error] <0.236.0>     messages: [{'EXIT',<0.237.0>,normal}]
jul 11 15:27:33 kaiyu-Latitude-5500 rabbitmq-server[935767]: 2023-07-11 15:27:33.512944+02:00 [error] <0.236.0>     links: [<0.235.0>,<0.44.0>]
jul 11 15:27:33 kaiyu-Latitude-5500 rabbitmq-server[935767]: 2023-07-11 15:27:33.512944+02:00 [error] <0.236.0>     dictionary: []
jul 11 15:27:33 kaiyu-Latitude-5500 rabbitmq-server[935767]: 2023-07-11 15:27:33.512944+02:00 [error] <0.236.0>     trap_exit: true
jul 11 15:27:33 kaiyu-Latitude-5500 rabbitmq-server[935767]: 2023-07-11 15:27:33.512944+02:00 [error] <0.236.0>     status: running
jul 11 15:27:33 kaiyu-Latitude-5500 rabbitmq-server[935767]: 2023-07-11 15:27:33.512944+02:00 [error] <0.236.0>     heap_size: 233
jul 11 15:27:33 kaiyu-Latitude-5500 rabbitmq-server[935767]: 2023-07-11 15:27:33.512944+02:00 [error] <0.236.0>     stack_size: 28
jul 11 15:27:33 kaiyu-Latitude-5500 rabbitmq-server[935767]: 2023-07-11 15:27:33.512944+02:00 [error] <0.236.0>     reductions: 168
jul 11 15:27:33 kaiyu-Latitude-5500 rabbitmq-server[935767]: 2023-07-11 15:27:33.512944+02:00 [error] <0.236.0>   neighbours:
jul 11 15:27:33 kaiyu-Latitude-5500 rabbitmq-server[935767]: 2023-07-11 15:27:33.512944+02:00 [error] <0.236.0>
jul 11 15:27:33 kaiyu-Latitude-5500 rabbitmq-server[935767]: 2023-07-11 15:27:33.519884+02:00 [notice] <0.44.0> Application rabbit exited with reason: {failed_to_initialize_feature_flags_registry,{rabbit,start,[normal,[]]}}
jul 11 15:27:35 kaiyu-Latitude-5500 rabbitmq-server[935767]: Kernel pid terminated (application_controller) ({application_start_failure,rabbit,{failed_to_initialize_feature_flags_registry,{rabbit,start,[normal,[]]}}})
jul 11 15:27:35 kaiyu-Latitude-5500 rabbitmq-server[935767]: 
jul 11 15:27:35 kaiyu-Latitude-5500 rabbitmq-server[935767]: Crash dump is being written to: erl_crash.dump...done
jul 11 15:27:35 kaiyu-Latitude-5500 systemd[1]: rabbitmq-server.service: Main process exited, code=exited, status=1/FAILURE
-- Subject: Unit process exited
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
-- 
-- An ExecStart= process belonging to unit rabbitmq-server.service has exited.
-- 
-- The process' exit code is 'exited' and its exit status is 1.
jul 11 15:27:35 kaiyu-Latitude-5500 systemd[1]: rabbitmq-server.service: Failed with result 'exit-code'.
-- Subject: Unit failed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
-- 
-- The unit rabbitmq-server.service has entered the 'failed' state with result 'exit-code'.
jul 11 15:27:35 kaiyu-Latitude-5500 systemd[1]: Failed to start RabbitMQ broker.
-- Subject: A start job for unit rabbitmq-server.service has failed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
-- 
-- A start job for unit rabbitmq-server.service has finished with a failure.
-- 
-- The job identifier is 299570 and the job result is failed.

What I have tried:

1. try to enable all the feature flags of rabbitmq by rabbitmqctl enable_feature_flag all and it did not work.
2. update the packages by sudo apt update and got some error messages about rabbitmq:

 Failed to fetch https://ppa1.novemberain.com/rabbitmq/rabbitmq-erlang/deb/ubuntu/dists/focal/main/binary-i386/Packages  404  Not Found [IP: 172.67.140.63 443]
E: Failed to fetch https://ppa1.novemberain.com/rabbitmq/rabbitmq-server/deb/ubuntu/dists/focal/main/binary-i386/Packages  404  Not Found [IP: 172.67.140.63 443]

Seems like the url does not exist anymore but I found nothing in their official documentation about this url. 3. I also tried to reinstall the rabbitmq-server package, but did not work.