If the antenna in question is still not working after taking into account the aforementioned tips, it is most likely that it is not suitable for your environmental conditions.
Unfortunately the physics of indoor aerial makes it quite difficult to troubleshoot them, as the reception quality can be affected by numerous factors related to the actual building and its surroundings (e.g. population density, building material, amount of electronic devices in the area, building density, environmental aspects such as mountains/valleys, humidity of air etc.).
