Certificate signature validation failed

Question

My website is hosted on Amazon. It is built on the microsoft version of java 1.4.2_13. I noticed emails were not going out. I had not made any changes to the code. I found this

Answer 1

Java itself got SHA256 support in 1.4.2, but the Microsoft Java may not- especially because it's been discontinued for a long time. You might be able to use bouncycastle.

Note Java 1.4 came out in 2002. That's 14 years ago. That should be a huge red flag; I wouldn't run that on any machine connected to the Internet.