LDAP error when logging into the Rancher UI after a Rancher upgrade

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Situation

After upgrading Rancher to version 2.6.9 or higher, the following error is seen after logging into the Rancher UI:

ldap error Error creating ssl connection: LDAP Result Code 200 "Network Error": tls: server selected unsupported protocol version 301

Resolution

Upgrade the version of TLS that the LDAP server uses to at least 1.2.

Cause

This problem happens when the LDAP server used for authentication with Rancher uses a version of TLS lower than 1.2.
Rancher 2.6.9 uses Go 1.19 where the crypto/tls library that is used requires a minimum version of TLS 1.2 for LDAP connections.

Disclaimer

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