The client and server cannot communicate because they do not possess a common algorithm


Users may run into issues with DNN after changing to TLS 1.2 connecting to/passing information to third-party services or systems. On checking the error logs, the following will be seen:

Error: The underlying connection was closed: An unexpected error occurred on a receive. The client and server cannot communicate, because they do not possess a common algorithm.



  • Access to the DNN file structure.



Based on the error message above, the third-party service is requiring the incoming connection from DNN to be authenticated using a protocol above TLS 1.0.

By default, DNN will only use TLS 1.0 for outgoing connections and you will need to implement the below solution to force outbound connections to use TLS 1.2.




1. Download the DotNetNuke.Security.Tls12.dll file from the Davidjrh Github repository.


2. Place the .dll file in the RootFolder/bin folder of the DNN installation. 



  • Check the previously broken connection with the third-party application or module by accessing it on the DNN site. Check the logs located in the RootFolder/Portals/_default/Logs folder. 



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