MongoDB Documentation, Release 3.0.4 you encounter this issue, add the sslverifycertificate=false option to the connection string to prevent the .NET driver from validating the certificate, as follows: var connectionString = "mongodb://localhost/?ssl=true&sslverifycertificate=false"; var server = MongoServer.Create(connectionString); For more details, see the .NET MongoDB Driver page$^{48}$. MongoDB Tools Changed in version 2.6. Various MongoDB utility programs supports SSL. These tools include: • mongodump • mongoexport • mongofiles • mongoimport • mongooplog • mongorestore • mongostat • mongotop To use SSL connections with these tools, use the same SSL options as the mongo shell. See mongo Shell SSL Configuration (page 346). Upgrade a Cluster to Use TLS/SSL Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL (page 342) and TLS/SSL Configuration for Clients (page 346) for more information about TLS/SSL and MongoDB. Important: A full description of TLS/SSL, PKI (Public Key Infrastructure) certificates, and Certificate Authority is beyond the scope of this document. This page assumes prior knowledge of TLS/SSL as well as access to valid certificates. Changed in version 2.6. The MongoDB server supports listening for both TLS/SSL encrypted and unencrypted connections on the same TCP port. This allows upgrades of MongoDB clusters to use TLS/SSL encrypted connections. To upgrade from a MongoDB cluster using no TLS/SSL encryption to one using only TLS/SSL encryption, use the following rolling upgrade process: 1. For each node of a cluster, start the node with the option --sslMode set to allowSSL . The --sslMode allowSSL setting allows the node to accept both TLS/SSL and non-TLS/non-SSL incoming connections. Its connections to other servers do not use TLS/SSL. Include other TLS/SSL options (page 342) as well as any other options that are required for your specific configuration. For example: mongod --replSet <name> --sslMode allowSSL --sslPEMKeyFile <path to TLS/SSL Certificate $^{48}$https://docs.mongodb.org/ecosystem/drivers/csharp Chapter 6. Security 350