User blog:GODZZwarmachine1997/Terraria 1.3 "This is not valid housing." PLEASE HELP!!!!!!!

OK there is a problem with my house that i just created using living wood and living wood furniture, in the sheet shot I am standing i the room that have the problem. The thing is after I made is room I place a NPC in there but it keeps saying that "This is not valid housing". Like what the heck I just checked everything and made sure there is not cracks on the walls and stuff but it keeps saying the same message over and over again. By the way my world did not enter hard mode nor did I build my house near the corruption. PLEASE can anyone gave me some ideas!!!!!

-Thanks in advance!!! <3