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TOP Server UA Certificate validation issue after 5.18 upgrade (Solved)

I am trying to connect to my TOP Server 5.18 using an OPC UA Client but am running into problems.  I have exchanged certificates yet I am unable to connect.

This issue is due to the large OpenSSL upgrade that happened in TOP Server in version 5.18. Prior to 5.18 TOP Server was using OpenSSL 0.9.8k, which was upgraded to 1.0.2d in version 5.18 (1.0.2h in 5.21). Because there was such a large jump in the OpenSSL version, there might be certificate validation errors when using the old certificate and we recommend generating a new one.

  1. Right click on the TOP server Icon in the System tray, and open the OPC UA Configuration Manager.
  2. Navigate to the Instance Certificates tab
  3. Use the "Reissue certificate" button to generate a new server and/or client certificate
  4. Use the "Export..." buttons to export the new certificates for use

Please note that there are other reasons why an OPC UA client might not be connecting to an OPC UA server, including mistyped endpoint URLs, mismatches security settings, and anonymous vs user authentication. This FAQ assumes that all other settings have been verified to be correct.