Trying to setup a second and third control plane node (without "-worker") both are stuck in "Provisioned". rke2-server log shows

Mar 26 16:00:04 kube005c01.ac.aixigo.de rke2[1313]: time="2024-03-26T16:00:04+01:00" level=info msg="Removing S3 snapshot: <s3://rancher02/kube005/etcd-snapshot-kube005c00.ac.aixigo.de-1711105204>"
Mar 26 16:00:04 kube005c01.ac.aixigo.de rke2[1313]: time="2024-03-26T16:00:04+01:00" level=info msg="Reconciling ETCDSnapshotFile resources"
Mar 26 16:00:06 kube005c01.ac.aixigo.de rke2[1313]: time="2024-03-26T16:00:06+01:00" level=info msg="Deleting ETCDSnapshotFile for etcd-snapshot-kube005c00.ac.aixigo.de-1711105204"
Mar 26 16:00:06 kube005c01.ac.aixigo.de rke2[1313]: time="2024-03-26T16:00:06+01:00" level=info msg="Reconciliation of ETCDSnapshotFile resources complete"
Mar 26 16:00:21 kube005c01.ac.aixigo.de rke2[1313]: time="2024-03-26T16:00:21+01:00" level=info msg="Connecting to proxy" url="<wss://172.19.96.54:9345/v1-rke2/connect>"
Mar 26 16:00:21 kube005c01.ac.aixigo.de rke2[1313]: time="2024-03-26T16:00:21+01:00" level=info msg="Handling backend connection request [kube005c02.ac.aixigo.de]"
Mar 26 16:00:23 kube005c01.ac.aixigo.de rke2[1313]: time="2024-03-26T16:00:23+01:00" level=info msg="Updating TLS secret for kube-system/rke2-serving (count: 18): map[field.cattle.io/projectId:c-m-8gb8bnjk:p-c54dp listener.cattle.io/cn-10.43.0.1:10.43.0.1 listener.cattle.io/cn-127.0.0.1:127.0.0.1 listener.cattle.io/cn-172.19.96.44:172.19.96.44 listener.cattle.io/cn-172.19.96.45:172.19.96.45 listener.cattle.io/cn-172.19.96.54:172.19.96.54 listener.cattle.io/cn-2a00_fe0_30_60__2c-aa8739:2a00:fe0:30:60::2c listener.cattle.io/cn-2a00_fe0_30_60__2d-8a7792:2a00:fe0:30:60::2d listener.cattle.io/cn-2a00_fe0_30_60__36-7193d4:2a00:fe0:30:60::36 listener.cattle.io/cn-__1-f16284:::1 listener.cattle.io/cn-kube005c00.ac.aixigo.de:kube005c00.ac.aixigo.de listener.cattle.io/cn-kube005c01.ac.aixigo.de:kube005c01.ac.aixigo.de listener.cattle.io/cn-kube005c02.ac.aixigo.de:kube005c02.ac.aixigo.de listener.cattle.io/cn-kubernetes:kubernetes listener.cattle.io/cn-kubernetes.default:kubernetes.default listener.cattle.io/cn-kubernetes.default.svc:kubernetes.default.svc listener.cattle.io/cn-kubernetes.default.svc.cluster.local:kubernetes.default.svc.cluster.local listener.cattle.io/cn-localhost:localhost listener.cattle.io/fingerprint:SHA1=1F54835EA0967FF7C1BA1A6F56A9431174D2AB77]"
Mar 26 16:00:23 kube005c01.ac.aixigo.de rke2[1313]: time="2024-03-26T16:00:23+01:00" level=info msg="Active TLS secret kube-system/rke2-serving (ver=71265216) (count 18): map[field.cattle.io/projectId:c-m-8gb8bnjk:p-c54dp listener.cattle.io/cn-10.43.0.1:10.43.0.1 listener.cattle.io/cn-127.0.0.1:127.0.0.1 listener.cattle.io/cn-172.19.96.44:172.19.96.44 listener.cattle.io/cn-172.19.96.45:172.19.96.45 listener.cattle.io/cn-172.19.96.54:172.19.96.54 listener.cattle.io/cn-2a00_fe0_30_60__2c-aa8739:2a00:fe0:30:60::2c listener.cattle.io/cn-2a00_fe0_30_60__2d-8a7792:2a00:fe0:30:60::2d listener.cattle.io/cn-2a00_fe0_30_60__36-7193d4:2a00:fe0:30:60::36 listener.cattle.io/cn-__1-f16284:::1 listener.cattle.io/cn-kube005c00.ac.aixigo.de:kube005c00.ac.aixigo.de listener.cattle.io/cn-kube005c01.ac.aixigo.de:kube005c01.ac.aixigo.de listener.cattle.io/cn-kube005c02.ac.aixigo.de:kube005c02.ac.aixigo.de listener.cattle.io/cn-kubernetes:kubernetes listener.cattle.io/cn-kubernetes.default:kubernetes.default listener.cattle.io/cn-kubernetes.default.svc:kubernetes.default.svc listener.cattle.io/cn-kubernetes.default.svc.cluster.local:kubernetes.default.svc.cluster.local listener.cattle.io/cn-localhost:localhost listener.cattle.io/fingerprint:SHA1=1F54835EA0967FF7C1BA1A6F56A9431174D2AB77]"
Mar 26 16:04:11 kube005c01.ac.aixigo.de rke2[1313]: 2024/03/26 16:04:11 ERROR: [transport] Client received GoAway with error code ENHANCE_YOUR_CALM and debug data equal to ASCII "too_many_pings".
Mar 26 16:09:01 kube005c01.ac.aixigo.de rke2[1313]: 2024/03/26 16:09:01 ERROR: [transport] Client received GoAway with error code ENHANCE_YOUR_CALM and debug data equal to ASCII "too_many_pings".

Sorry for asking, but what is this supposed to tell me? Rancher is version 2.8.2, self-hosted cluster, rke2 1.27.11