There are no restrictions on your membership. At this point in time, only two videos are playable from one account. This is to ensure that your membership is not misused.
In case you see an error that says you are trying to access videos from more than two devices, please check if people are already streaming videos at the same time from your account. To continue watching the current video, make sure you have stopped the earlier videos. Refresh on current device to continue watching the video.