_PushStatus error while sending push message

Hi guys,

I have a Node.js server that has been working fine for years. Recently, the push notification started to fail in the same error message:

The error looks like this:

error: _PushStatus Z4rB5vvHHf: error while sending push message=connection 5 to xx.mongodb.net:27017 timed out, stack=MongoNetworkError: connection 5 to xx.mongodb.net:27017 timed out at processTimers (node:internal/timers:500:7), name=MongoNetworkError, errorLabels=[TransientTransactionError]

The _PushStatus object of the failed notification looks like this:

“_id”: “…”,
“pushTime”: “2023-12-14T08:47:18.443Z”,
“query”: “…”,
“payload”: “…”,
“source”: “rest”,
“status”: “failed”,
“numSent”: {
“$numberInt”: “0”
“pushHash”: “xx”,
“_wperm”: ,
“_rperm”: ,
“_acl”: {},
“_created_at”: {
“$date”: {
“$numberLong”: “1702543638443”
“_updated_at”: {
“$date”: {
“$numberLong”: “1702543998473”
“errorMessage”: {
“name”: “MongoNetworkError”,
“errorLabels”: [

No code changes or database changes at all for years.

What is TransientTransactionError and how should I debug this error?