JSSL0080E: javax.net.ssl.SSLHandshakeException - The client and server could not negotiate the desired level of security.
then big chance is that there's something wrong with internal certificates between WAS instances, either:
1. Hostname has been changed and hostname verification is turned on in SSL setup. you may check this here:
The default trust manager, IbmX509, performs fundamental certificate validation, including the certificate signature validation (ensuring it has not been modified) and certificate expiration validation (ensuring it has not expired). This trust manager does not perform hostname verification by default, although you can set the com.ibm.ssl.performURLHost
(recommend reading the whole article btw.)
2. Something went horribly wrong in terms of cell synchronization, so I'd suggest stopping servers and nodeagent on remote machine and running ./syncNode.sh from profile's bin directory. not sure it will work as probably wsadmin script client won't be able to connect to SOAP port due to root cause. hence, we're back at point 1. and I guess only manual copying of trust/keystores from dmgr machine to remote machine might help.
hope this helps, or at least points to the right direction.