Errors concerning failed connections - - Alibaba Cloud Documentation Center

This topic describes the common errors that may occur when you fail to connect to an ApsaraDB for MongoDB instance.

Error message	Cause	Solution
`network error while attempting to run command 'isMaster' on host 'dds-bpxxxxxxxx.mongodb.rds.aliyuncs.com:3717' :exception: connect failed` `Timed out after 3000ms while waiting for a server that matches ReadPreferenceServerSelector{readPreference=primary}. exception=(com.mongodb.MongoSocketReadException: Prematurely reached end of stream)` `Socket recv() errno:54 Connection reset by peer 1.2.3.4:27017`	The maximum number of connections to the ApsaraDB for MongoDB instance is reached.	For more information about common solutions, see the following topics: How do I query and limit the number of connections? How do I troubleshoot failed database connections after the number of connections reaches the upper limit? What do I do if the "Connection reset by peers" error is returned when I try to establish a connection to an ApsaraDB for MongoDB instance by using the mongo shell?
`Failed to connect to 10...8:3717 after 5000 milliseconds, giving up.Error: couldn't connect to server 10...8:3717 (10.1.2.8), connection attempt failed` `pymongo.errors.ServerSelectionTimeoutError: dds-xxx.mongodb.rds.aliyuncs.com:3717: [Errno 113] No route to host,dds-xxx.mongodb.rds.aliyuncs.com:3717`	An Elastic Compute Service (ECS) instance fails to connect to the ApsaraDB for MongoDB instance over a private network.	The ECS instance and ApsaraDB for MongoDB instance must meet all of the following requirements: The private IP address of the ECS instance is added to a whitelist of the ApsaraDB for MongoDB instance. The instances communicate with each other. The ECS instance is deployed in the same virtual private cloud (VPC) as the ApsaraDB for MongoDB instance and connects to another instance over a private network. If you want to connect the ECS instance to the ApsaraDB for MongoDB instance across VPCs, perform one of the following operations: Migrate the instances to the same VPC. For more information, see Connect an ECS instance to an ApsaraDB for MongoDB instance in a different region over the internal network or Connect an ECS instance to an ApsaraDB for MongoDB instance within a different Alibaba Cloud account over the internal network. Make sure that the CIDR blocks to be connected do not conflict with each other and allow you to establish connections in different VPCs. For more information, see Method 3: Establish a connection between the ECS instance and the ApsaraDB for MongoDB instance by using CEN.
`Error: network error while attempting to run command 'isMaster' on host 'ft12345678.mongodb.rds.aliyuncs.com:3717'`	An IP address whitelist of the ApsaraDB for MongoDB instance does not contain the IP address from which you want to connect to the instance.	Check the IP address whitelist of the ApsaraDB for MongoDB instance and add the correct IP address of the ECS instance to the whitelist of another instance. For more information about how to configure a whitelist, see Modify an IP address whitelist for an instance.
`org.springframework.data.mongodb.UncategorizedMongoDbException: Timeout while receiving message; nested exception is com.mongodb.MongoSocketReadTimeoutException: Timeout while receiving message`	Slow queries occupy instance resources.	For more information about common solutions, see the following topics: Troubleshoot high memory usage issues on an instance Troubleshoot high CPU utilization issues on an instance Troubleshoot high IOPS utilization issues on an instance Troubleshoot high disk utilization issues on an instance
`"errmsg": "not master", "code": 10107, "codeName": "NotMaster"` `"errmsg": "not master", "code": 10107, "codeName": "NotWritablePrimary"` `Time out after 30000ms while waiting for a server that matches writableServerSelector.`	Data is not written to the primary node of a replica set instance.	For more information about common solutions, see Why is the "NotMaster", "NotWritablePrimary", or "Time out after 30000ms while waiting for a server that matches writableServerSelector" error message is returned when data is written to a replica set instance?
`reason: TopologyDescription { type: 'ReplicaSetNoPrimary',`	No primary node is available in the currently connected replica set instance.	Common solutions include: Use the connection string URI to connect to the instance. For more information about how to obtain the connection string URI, see Connect to a replica set instance. Manually switch the node role of the instance. For more information about how to switch the node role, see Switch node roles.
`[Unauthorized] cloud instance error, disk locked, plz check and upgrade your disk quota,`	The instance is locked because the disk is full.	For more information about common solutions, see What do I do if an instance is locked or data cannot be written to the instance due to exhausted disk space?
`(AuthenticationFailed) Authentication failed.`	The password used to log on to the database is incorrect. The name of the authentication database in the instance endpoint is incorrect.	Common causes and solutions include: Incorrect password Solution: Reset the password and try again. For more information about how to reset a password, see Reset the password of an account for an instance. Incorrect authentication database Solution: Check the connection address of the instance and enter the correct authentication database in the connection string. The authentication database is used to store database accounts and passwords. For the authentication to succeed, the specified database account must belong to the specified authentication database.
`!xxx@dds-xxx.mongodb.rds.aliyuncs.com: event not found` `Authentication failed.`	The password contains one or more of the following special characters: `! @ # $ % ^ & * ( ) _ + =`	Escape the special characters. For more information, see What do I do if my instance is not connected due to special characters in the password in the connection string of the instance?
`error getting cluster ID: (CommandNotFound) replSetGetConfig is forbidden by cloud provider for security reason`	The `replSetGetConfig` command is not supported on ApsaraDB for MongoDB.	What commands are supported and not supported by ApsaraDB for MongoDB?