Postgres networking issues

[The-Compiler]

Every once in a while (currently February 11th and March 28th), I get:

OperationalError at /events/calendar.ics
could not translate host name "postgres" to address: Name or service not known

or

OperationalError at /dokumente/urbdes2/424/
could not connect to server: Connection refused
	Is the server running on host "postgres" (172.19.0.3) and accepting
	TCP/IP connections on port 5432?

Latest one, at 00:55:48, system log shows:

Mar 28 00:55:45 vshsr01 dockerd[12411]: time="2023-03-28T00:55:45.621957742+02:00" level=info msg="ignoring event" container=2f81b99a314fc7b6811c8dff6290090e92e015b705a5ef2392972bea854642f6 module=libcontainerd namespace=moby topic=/tasks
Mar 28 00:55:45 vshsr01 containerd[9458]: time="2023-03-28T00:55:45.627553469+02:00" level=info msg="shim disconnected" id=2f81b99a314fc7b6811c8dff6290090e92e015b705a5ef2392972bea854642f6
Mar 28 00:55:45 vshsr01 containerd[9458]: time="2023-03-28T00:55:45.628540918+02:00" level=warning msg="cleaning up after shim disconnected" id=2f81b99a314fc7b6811c8dff6290090e92e015b705a5ef2392972bea854642f6 namespace=moby
Mar 28 00:55:45 vshsr01 containerd[9458]: time="2023-03-28T00:55:45.628597120+02:00" level=info msg="cleaning up dead shim"
Mar 28 00:55:45 vshsr01 containerd[9458]: time="2023-03-28T00:55:45.696811451+02:00" level=warning msg="cleanup warnings time=\"2023-03-28T00:55:45+02:00\" level=info msg=\"starting signal loop\" namespace=moby pid=6748 runtime=io.contain
Mar 28 00:55:45 vshsr01 kernel: br-9ea64536c35d: port 2(vetha5a6c1d) entered disabled state
Mar 28 00:55:45 vshsr01 kernel: veth0147ed9: renamed from eth0
Mar 28 00:55:45 vshsr01 kernel: br-9ea64536c35d: port 2(vetha5a6c1d) entered disabled state
Mar 28 00:55:45 vshsr01 kernel: device vetha5a6c1d left promiscuous mode
Mar 28 00:55:45 vshsr01 kernel: br-9ea64536c35d: port 2(vetha5a6c1d) entered disabled state
Mar 28 00:55:46 vshsr01 kernel: br-9ea64536c35d: port 2(veth36a87e9) entered blocking state
Mar 28 00:55:46 vshsr01 kernel: br-9ea64536c35d: port 2(veth36a87e9) entered disabled state
Mar 28 00:55:46 vshsr01 kernel: device veth36a87e9 entered promiscuous mode
Mar 28 00:55:46 vshsr01 kernel: IPv6: ADDRCONF(NETDEV_UP): veth36a87e9: link is not ready
Mar 28 00:55:46 vshsr01 kernel: br-9ea64536c35d: port 2(veth36a87e9) entered blocking state
Mar 28 00:55:46 vshsr01 kernel: br-9ea64536c35d: port 2(veth36a87e9) entered forwarding state
Mar 28 00:55:46 vshsr01 kernel: br-9ea64536c35d: port 2(veth36a87e9) entered disabled state
Mar 28 00:55:46 vshsr01 containerd[9458]: time="2023-03-28T00:55:46.814186773+02:00" level=info msg="loading plugin \"io.containerd.event.v1.publisher\"..." runtime=io.containerd.runc.v2 type=io.containerd.event.v1
Mar 28 00:55:46 vshsr01 containerd[9458]: time="2023-03-28T00:55:46.814389636+02:00" level=info msg="loading plugin \"io.containerd.internal.v1.shutdown\"..." runtime=io.containerd.runc.v2 type=io.containerd.internal.v1
Mar 28 00:55:46 vshsr01 containerd[9458]: time="2023-03-28T00:55:46.814453811+02:00" level=info msg="loading plugin \"io.containerd.ttrpc.v1.task\"..." runtime=io.containerd.runc.v2 type=io.containerd.ttrpc.v1
Mar 28 00:55:46 vshsr01 containerd[9458]: time="2023-03-28T00:55:46.864772508+02:00" level=info msg="starting signal loop" namespace=moby path=/run/containerd/io.containerd.runtime.v2.task/moby/6a92ce393d9d3c5b12e35b42655349f840b44b86e763
Mar 28 00:55:47 vshsr01 kernel: eth0: renamed from veth4c56d9a
Mar 28 00:55:47 vshsr01 kernel: IPv6: ADDRCONF(NETDEV_CHANGE): veth36a87e9: link becomes ready
Mar 28 00:55:47 vshsr01 kernel: br-9ea64536c35d: port 2(veth36a87e9) entered blocking state
Mar 28 00:55:47 vshsr01 kernel: br-9ea64536c35d: port 2(veth36a87e9) entered forwarding state

not sure what's going on there? Is this watchtower restarting docker or something?