Try verifying local files: in the Steam library, right click on the game and select Properties, switch to the Local Files tab and then click on the 'Verify Integrity of Game Cache...' button.
With the GOG version, in the (optional) Galaxy client, select Divinity: Original Sin 2 in the left column, then click on the More button, and in the Manage menu select 'Verify / Repair'.
Is Lohse in the party and present at the Black house? I assume you didn't enter previously without Lohse in your party, refuse a deal and been kicked out?
If so, please email your latest save (or a Dropbox or Google drive link, etc) to supportdos2@larian.com, as well as the most recent save where you can open or get a response from the door, and the oldest were it is unresponsive.
Each save is a folder in the '..\Documents\Larian Studios\Divinity Original Sin 2\PlayerProfiles\<ProfileName>\Savegames\Story' folder.
In Windows Explorer you can zip file(s) and folder(s) by right clicking on it/them and selecting 'Send To | Compressed (zipped) Folder'.
Please do the same with your latest save or one at the end of the Line of Anguish, as well as your save before entering that section, if available.