Help! The rbd-target-api service of iSCSI gw cannot be started

Help! The rbd-target-api service of iSCSI gw cannot be started

Two servers form iSCSI GW,

[root@ceph-node1 ~]# systemctl reset-failed rbd-target-api.service
[root@ceph-node1 ~]# systemctl start rbd-target-api.service
[root@ceph-node1 ~]# gwcli
Unable to access the configuration object : REST API failure, code : 500
GatewayError:
[root@ceph-node1 ~]# systemctl status rbd-target-api
● rbd-target-api.service - Ceph iscsi target configuration API
Loaded: loaded (/usr/lib/systemd/system/rbd-target-api.service; enabled; vendor preset: disabled)
Active: failed (Result: start-limit) since Fri 2021-07-30 11:25:58 CST; 15min ago
Process: 11678 ExecStart=/usr/bin/rbd-target-api (code=exited, status=1/FAILURE)
Main PID: 11678 (code=exited, status=1/FAILURE)

Jul 30 11:25:58 ceph-node1 systemd[1]: Unit rbd-target-api.service entered failed state.
Jul 30 11:25:58 ceph-node1 systemd[1]: rbd-target-api.service failed.
Jul 30 11:25:58 ceph-node1 systemd[1]: rbd-target-api.service holdoff time over, scheduling restart.
Jul 30 11:25:58 ceph-node1 systemd[1]: Stopped Ceph iscsi target configuration API.
Jul 30 11:25:58 ceph-node1 systemd[1]: start request repeated too quickly for rbd-target-api.service
Jul 30 11:25:58 ceph-node1 systemd[1]: Failed to start Ceph iscsi target configuration API.
Jul 30 11:25:58 ceph-node1 systemd[1]: Unit rbd-target-api.service entered failed state.
Jul 30 11:25:58 ceph-node1 systemd[1]: rbd-target-api.service failed.
[root@ceph-node1 ~]#

This is where is the problem, how to troubleshoot this kind of need
Thank you very much for your answer