asp.net - POST request hangs at "pending" -

i have room , room contains 0 or more devices. have controller, roomcontroller. here's simplified version of controller:

[responsetype(typeof(room))] public ihttpactionresult postroom(newroom newroom) {     ...     room room = new room();     room.building_id = newroom.building_id;     ...and soforth...      if(newroom.devices != null)     {         foreach (devicenew newdevice in newroom.devices)         {             device device = db.devices.firstordefault(d => d.id == newdevice.id);             room.devices.add(device);         }     }      db.savechanges();     return ok(room); } 

the controller works. room created, attached devices. sadly, post request never returns if there devices included in request. is, in chrome dev tools, request remains "pending" forever.

if there aren't devices, request returns 200, expected.

again, controller works, devices included. records created. route doesn't return ok way should.

am missing something?

thanks!

edit:

the room model (simplified):

namespace thething.models_database {     using system;     ...      public partial class room     {         public room()         {             devices = new hashset<device>();         }          public int id { get; set; }          public virtual icollection<device> devices { get; set; }     } } 

and device model (simplified):

namespace thething.models_database {     using system;     ...      public partial class device     {         public device()         {             ...             rooms = new hashset<room>();         }          public int id { get; set; }         ...         public virtual icollection<room> rooms { get; set; }     } }