Unjustified sanction-rejection of my paper: Scientific Reports

I am here to get help regarding an unjustified sanction and the withdrawal of my paper from Scientific Reports

After 3 rounds of review of my manuscript, my paper entered the final Springer screening process, where it was flagged by the Journal Editorial Office (JEO) and removed from the system because the (co-) authors are potentially from UN- or internationally sanctioned territories (that’s at least how I understand the rather cryptic email from the Springer office). All authors have South Korean affiliations, and we are Indian, German, Dutch, US, and South Korean nationals. So there is no issue of political sanctions or sanctioned territories. 

I would really appreciate it if anyone could suggest the right channel for contacting and resolving the issue.