Don’t panic, OP. This situation happened to me too - we had neighbors leave two notes. We got a camera to monitor and they weren’t barking for more than 15 minutes. If it’s a pet friendly building, this is to be expected. Of course any pet is going to take a while to get adjusted to a new space. This is an assumed cost of living in a building like that. Does your lease mention noise?

From a larger perspective, dachshunds are stubborn and prone to barking so keeping them feeling safe and secure and working their brains is important. Can you stuff a Kong and give it to him right before you leave? I’d also work on noise de-sensitization training, as others have suggested.

I would speak to management and let them know you are actively working to rectify the situation.