Mongodb-gap peering not working

Hi I am getting the following error when nodes app is trying to access Atlas db from google app engine. Following steps I followed

  1. Upgrade to M10 cluster
  2. Created a VPC network on GAE
  3. Created a mongodb peering connection with GAE project id & VPC network
  4. Created a reciprocal connection on GAE side with mongo atlas Project ID & Project Name
  5. Connections on both the sides are active.
  6. Added default atlas CIDR in IP white list
  7. Try to access db through GAE node app. Verified the connection string url is correct, tried to access db locally with local ip white list, the same issue occured
    Getting following error.

Note: ‘xxx’ is place holder

Any suggestion on how to resolve this issue?

    reason: TopologyDescription {
      type: 'ReplicaSetNoPrimary',
      servers: Map {
       '' => [ServerDescription],
        '' => [ServerDescription],
       '' => [ServerDescription]
      stale: false,
      compatible: true,
      heartbeatFrequencyMS: 10000,
      localThresholdMS: 15,
      setName: 'atlas-7rmoin-shard-0',
      maxElectionId: null,
      maxSetVersion: null,
      commonWireVersion: 0,
      logicalSessionTimeoutMinutes: null
    code: undefined,
   [Symbol(errorLabels)]: Set {}

Hi @Harsh_Koshti,

Are there 2 connections created? Or do you mean that you accepted the initiated connection and a single connection appears in the Peering tab of Atlas (that has state Active)?

As per the GCP Set up a Network Peering Connection documentation:

You must add your VPC CIDR block address (or subset) associated with the peer VPC to the IP access list before your new VPC peer can connect to your Atlas cluster.

Did you add the Atlas CIDR to the IP access list or the GCP VPC associated with your GAE environment?

Lastly, just to be sure, please go over the Network Peering between an Atlas VPC and Two Virtual Networks with Identical CIDR Blocks documentation to confirm you don’t have overlapping CIDR’s.