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M
cr_unknown_host
Moderate
MySQL · Connector / Client Library
MySQL client error 2005: UNKNOWN HOST.
Quick Answer
Error code CR_UNKNOWN_HOST on your MySQL Connector / Client Library means: MySQL client error 2005: UNKNOWN HOST.. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
MYSQL-CLIMYSQL-CONNECTOR-CMYSQL-CONNECTOR-NODEMYSQL-CONNECTOR-PYMYSQL-SHELLMYSQL-WB
Likely Causes
  1. MySQL client emitted CR_UNKNOWN_HOST during connection/statement handling.
  2. Network path instability interrupted request/response exchange with the service endpoint.
  3. TLS, DNS, or socket negotiation failed before the operation could complete.
How to Fix It
1
Capture client and server logs for CR_UNKNOWN_HOST, including host, port, TLS mode, and statement context.
2
Verify firewall/proxy/network rules and regional endpoint targeting for the workload.
3
Capture endpoint, DNS resolution, TLS handshake, and socket metrics at failure time.
4
Retry with bounded exponential backoff and idempotency protection where possible.
5
Track CR_UNKNOWN_HOST frequency by environment to detect regressions early.
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Related Error Codes
CR_UNKNOWN_ERRORCR_SOCKET_CREATE_ERRORCR_CONNECTION_ERRORCR_CONN_HOST_ERRORCR_IPSOCK_ERROR
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