Guild Wars 2

I was waiting for a world boss and someone random pm’d me, I tried to answer but when I pressed enter to send, nothing happened. I didn’t get a message that says this person is offline and I know that he/she hasn’t blocked me since I’ve never met them before. Can I somehow fix this? It’s happened 2 times now when random ppl whispered me.

Perhaps they were “invisible”. I’ve forgotten to change my status to “Online” a time or two, myself.