Sims 4: My sims can't walk through any door

Try playing another household for a short time, then go back to your household and see if that helps. 
Also having her travel to another world and back may help.

This just happened to me as well. I've been playing in this house for 10 days in game without any issues. Suddenly my Sim is unable to get inside her house. I didn't change anything on the lot. There are two doors to get into the house and she won't use either of them. I've verified that they aren't locked, and I've tried resetting the sim and the doors without any luck. 

This just happened to me. things were fine* for about an hour. Then my Sim was outside after taking out the trash and suddenly could not enter her house. Before they were using the doors fine. The cat used the door fine too.

I was panicked, reset her. She had a newborn and an infant inside the house and they can't be left alone. I had to delete the walls of the house to allow her back* inside the house. I will try moving the family away and back next. 

Edit: moving them away to another home fixed it.

I had something similar.  It happened to two members of the same household.  When they got back from work, they would stay outside.  Try to get them to move inside to do anything and they’d shrug their shoulders.

Trying to exit without saving didn’t resolve the issue as the same would happen after they went outside.  Removing and re-adding the door would not work.  Adding a door to another wall would not allow them to come inside. They were acting as if they were locked outside but the door was set to allow them in.

Eventually I transferred those two to another household and transferred them back to the original.  That worked and I was relieved, but was very annoying.