This Article Applies to:

Omada SDN Controller (Windows & Linux)

Issue Description/Phenomenon:

The SMTP service for the Omada SDN Controllers fails after upgrading to Java_8u291(Windows) or OpenJDK_1.8.0_292(Linux). The phenomenon is that the mail server stops working on the Omada Controller and you may get the error "Send mail exception Could not connect to SMTP host".

A related post described the problem HERE. 

Note: 

If you are not sure which Java version you are using, please refer to the link below to have a check:

https://java.com/en/download/help/version_manual.html

Available Solutions:

TP-Link team has located the problem and will fix the issue in the subsequent updates later.

As a temporary solution, you can fix the issue by manually modifying the java configuration file as below:

Open the "java.security" file, find "jdk.tls.disabledAlgorithms" as shown in the following picture,

delete "TLSv1, TLSv1.1," to enable TLSv1 and 1.1, and save the changes;

then restart the Omada SDN Controller.

Note:

• For Windows, the default path of the file is "C:Program Files Javajre1.8.0_291libsecurity" or

"C:Program Files (x86)Javajre1.8.0_291libsecurity".

• For CentOS/Fedora, the default path is "/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.292.b10-1.el7_9.x86_64/jre/lib/security/java.security".
• For Debian/Ubuntu, the default path is "/etc/java-8-openjdk/security/java.security".

Reference: https://bugs.java.com/bugdatabase/view_bug.do?bug_id=JDK-8202343