ReplicaSetNoPrimary error although primary exists - node.js

Question

I have recently upgraded my mongodb setup from a standalone to a replica set. It seems as the error is caused by the replica set not having a primary (ReplicaSetNoPrimary), so I checked the replica set status but it seems fine to me (only member is the primary). Note that the connection worked before upgrading to a replica set.
Connection:
const options = {
useUnifiedTopology: true,
serverSelectionTimeoutMS: 30000,
socketTimeoutMS: 75000,
keepAlive: true,
};
const client = new MongoClient(
`mongodb://${username}:${password}#localhost:27017/?authSource=admin&replicaSet=rs0&retryWrites=true`,
options,
);
await client.connect();
Error:
/home/script/node_modules/mongodb/lib/sdam/topology.js:325
const timeoutError = new error_1.MongoServerSelectionError(`Server selection timed out after ${serverSelectionTimeoutMS} ms`, this.description);
^
MongoServerSelectionError: connection <monitor> to 127.0.0.1:27017 timed out
at Timeout._onTimeout (/home/script/node_modules/mongodb/lib/sdam/topology.js:325:38)
at listOnTimeout (node:internal/timers:557:17)
at processTimers (node:internal/timers:500:7) {
reason: TopologyDescription {
type: 'ReplicaSetNoPrimary',
servers: Map(1) {
'127.0.0.1:27017' => ServerDescription {
_hostAddress: HostAddress { isIPv6: false, host: '127.0.0.1', port: 27017 },
address: '127.0.0.1:27017',
type: 'Unknown',
hosts: [],
passives: [],
arbiters: [],
tags: {},
minWireVersion: 0,
maxWireVersion: 0,
roundTripTime: -1,
lastUpdateTime: 3298259072,
lastWriteDate: 0,
topologyVersion: {
processId: ObjectId { [Symbol(id)]: [Buffer [Uint8Array]] },
counter: 6
},
error: MongoNetworkTimeoutError: connection <monitor> to 127.0.0.1:27017 timed out
at Connection.handleIssue (/home/script/node_modules/mongodb/lib/cmap/connection.js:116:23)
at Socket.<anonymous> (/home/script/node_modules/mongodb/lib/cmap/connection.js:63:41)
at Socket.emit (node:events:394:28)
at Socket._onTimeout (node:net:486:8)
at listOnTimeout (node:internal/timers:557:17)
at processTimers (node:internal/timers:500:7) {
[Symbol(beforeHandshake)]: false
}
}
},
stale: false,
compatible: true,
heartbeatFrequencyMS: 10000,
localThresholdMS: 15,
setName: 'rs0',
maxSetVersion: 1,
maxElectionId: ObjectId {
[Symbol(id)]: Buffer(12) [Uint8Array] [
127, 255, 255, 255, 0,
0, 0, 0, 0, 0,
0, 2
]
},
commonWireVersion: 13,
logicalSessionTimeoutMinutes: undefined
}
}
Replica Set Status
rs0 [direct: primary] admin> rs.status().members
[
{
_id: 0,
name: '127.0.0.1:27017',
health: 1,
state: 1,
stateStr: 'PRIMARY',
uptime: 13174,
optime: { ts: Timestamp({ t: 1633978566, i: 89 }), t: Long("2") },
optimeDate: ISODate("2021-10-11T18:56:06.000Z"),
syncSourceHost: '',
syncSourceId: -1,
infoMessage: '',
electionTime: Timestamp({ t: 1633965396, i: 1 }),
electionDate: ISODate("2021-10-11T15:16:36.000Z"),
configVersion: 1,
configTerm: 2,
self: true,
lastHeartbeatMessage: ''
}
]