replication fails with aborted connection to db

Hi everyone, i have a question regarding a 2 nod master slave replication setup. The nodes are on different machines in the network in docker containers. The replication using xtrabackup-v2 keeps failing (immediately) with the error aborted connection to db… got an error reading communications packets (also see attached screenshot). I have scoured the internet for solutions for this problem but to no avail. Does anybody have an idea?

So far already tried:
-MySQL Error Reading Communication Packets - Database Administrators Stack Exchange (set to 1G)
-MySQL "Got an error reading communication packet" - Percona Database Performance Blog
-disabled selinux
-checked firewalld ports open and used nmap to verify
-The user for sst is present in every database, have all the permissions needed (and i can connect using the mysql command line).

I literally dont know what else to try anymore. The weird thing is that using replication with another server in the network is working…

anybody have any idea?

You are getting error with sstuser. Wondering if you can try using different user or may just root user.