Were you able to check the option snapmirror.access... legacy/all/hostnames? Post its output and also output of snapmirror.allow file. Do let me know are you using any snapcreator with https authentication.
snapmirror.access ( Should be changed legacy or hostname )
Make sure your destination has entry in the host files ( In case if you are not using any resolver ) and also make sure that dest controller is defined in the snapmirror.allow file ( can be found under /etc , whcih can be accessed from vol0 )
Ex:- snapmirror.access command
filerA>options snapmirror.access host=filerB,filerC ( Can mention IP address as well )