Baby sleep issue

There could be a couple of reasons. It's very common for even the best sleepers to suddenly start having problems, whether it's trouble falling asleep at bedtime or abruptly waking up during the night. Starting at age 6 months, separation anxiety can cause babies to wake up crying more than once during the night. Don't be surprised if your anxious baby does this and wants only you or only your partner. First, make sure that your little one is getting enough sleep in general. It may seem counterintuitive, but the less sleep babies get, the more likely they are to have trouble settling down at bedtime and staying asleep through the night. So be consistent about putting your baby to bed for naps during the day and getting him to bed at a reasonable time in the evening. When your baby wakes up during the night, be soothing and calming, but boring. Let him know that everything is okay, but that it's time to sleep. Stay with him until he's calm, but keep the conversation to a minimum and the lights dim. It may take a few nights or even a few weeks to get back on track, but the closer you stick to your baby's regular sleep routine, the sooner the problem will be resolved.