Our mini dachshund of 5 1/2 months is crated at night. He has done great, but all of a sudden, he is crying, barking, scratching for a long time when we put him in his crate at night.

Keep him out longer,he is only a baby and has probably bonded with you. Dogs are very social, as you no doubt know and he wants to be with you, cuddled and patted, taken for walks, etc. He needs love and attention.

Tick

We walk him and play with him a good bit at night. He has done great in the crate until just lately. No changes in what we are doing. He is only in the crate at night and has done well with it.

Try leaving a radio playing softly, or a ticking clock. Is there any reason you have to crate at night? Where is the crate now? How much exercise is he getting through out the day? What does he have in the crate to keep his mind occupied? Is he being walked right before going in the crate? IS there fresh water in the crate?

Where is the crate?

I had the same issue with my 4 month old pup, we had his crate in the living room and he screamed all night.

We moved it into the bedroom and things improved, but when I took away my bedside table and put his crate right next to the bed he slept soundly all night.

Sometimes they get a bit scared at night and just want to know you are close by.
I completely cover the crate with a blanket but when I hop in bed, I pull the blanket aside a bit so we can see each other until he goes to sleep, then cover him back over.