How many years do you have with your husband? Have you sent photos, letters, SMS etc with your file? How long from your application did they ask for more documents? Sorry for a lot of questions. I wish to you all the bestIt is something very hard to receive and I hope no one would go through it!!
It’s basically when the immigration officer is not satisfied with your file and to be (fair) to you he would ask you to submit more documents as a last chance prior to making a final decision