I find Alexa has trouble with names at times. I added 2 more WEMO's to my setup. One was for a JBOD and I just called it "Server". WEMO app had not problems with it but Alexa couldn't come to grips with it at all. The top light would spin and then nothing. I try again and the top light spins then 2 tones and nothing. I try again and then she tells me she can't find a song named "server" in my music library. I had to change the name to "dataserver" then she could deal with it. sheeesh..
something similar happened to me, I had to change one of my wemos names because of alexa not wanting to acknowledge it. I called it tv to turn on the tv and worked for months, then all of the sudden it took around 10 tries each time giving the spill about not being found. Looked in the log and it was hearing it right but just did not want to find it in order to turn it on. No problem turning it off. I ended up just renaming it to television and no more problems. I wonder if it became a reserved name amazon was planning to use later for something.