SQL Agent fails on SQL Server 2005

The error log from starting sqlagent is the following:
[298] SQLServer Error: 21, Encryption not supported on the client. [SQLSTATE 08001]
[298] SQLServer Error: 21, Client unable to establish connection [SQLSTATE 08001]
[165] ODBC Error: 0, An error has occurred while establishing a connection to the server. When connecting to SQL Server 2005, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections. [SQLSTATE 08001]
[000] Unable to connect to server '\SQL2005'; SQLServerAgent cannot start
[298] SQLServer Error: 21, Encryption not supported on the client. [SQLSTATE 08001]
[298] SQLServer Error: 21, Client unable to establish connection [SQLSTATE 08001]
[165] ODBC Error: 0, An error has occurred while establishing a connection to the server. When connecting to SQL Server 2005, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections. [SQLSTATE 08001]
[382] Logon to server '\SQL2005' failed (DisableAgentXPs)
[098] SQLServerAgent terminated (normally)

Resolution:
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Client side setting would have messed up. Please go to SQL Server Configuration Manager and click properties for "SQL Native Client Configuration", if correct, you should be able to see two flags, one is "force client encryption", the other one is "trust server certificate" and value were set "yes" or "no".

If you see "No properties are available", that means your client registry key was messed up and leads to the connection error . To fix this, suggest reinstall SNAC(SQL Native Client). Just run the sqlncli.msi