I can't access the March Monthly Mission any longer, is it broke?
I had similar issues. It appears, at least in my case it was an issue with chrome. I switched over to edge and it is working fine for me there.
Chrome had also generated the same issue in trying to send a message.
I had emailed @KMSigma.SWI out of band reporting this issue.
thanks jfrazier, loaded it up in FF and all is well. Chrome has failed us.