After upgrading PPM to version 10.0.1, the below error can be found when updating Project/Request or adding an attachment:

Header message of length [65,532] received but the packetSize is only [40,000]

After changing packetSize value to 65535 in server.xsl, above packetSize error disappeared; however, there is still an AJP error:

Caused by: java.lang.IndexOutOfBoundsException
at java.nio.Buffer.checkBounds(Buffer.java:572)
at java.nio.HeapByteBuffer.get(HeapByteBuffer.java:152)
at org.apache.tomcat.util.net.NioEndpoint$NioSocketWrapper.read(NioEndpoint.java:1208)
at org.apache.coyote.ajp.AjpProcessor.read(AjpProcessor.java:1231)
at org.apache.coyote.ajp.AjpProcessor.readMessage(AjpProcessor.java:593)
at org.apache.coyote.ajp.AjpProcessor.receive(AjpProcessor.java:533)
at org.apache.coyote.ajp.AjpProcessor.refillReadBuffer(AjpProcessor.java:640)
at org.apache.coyote.ajp.AjpProcessor$SocketInputBuffer.doRead(AjpProcessor.java:1298)

Full article: https://portal.microfocus.com/s/article/KM000017714