I have also been experiencing this since the last update. My error code is 123:7f04d1a6:f2568ce. I have noticed that I have no access to all lots within certain worlds. The worlds I have no current access to due to the error:
Del Sol Valley, Britechester, Copperdale
Worlds I have no access to because I don't own the packs: Chestnut Ridge, Tomarang
I can try to travel to any lot within the aforementioned worlds and I will get the error code. I only have one game affected and that is the one made since the update came down. None of the games made prior to the update have been affected. The affected game does have full access to the vacation worlds (Batuu, Granite Falls, Selvadorada). I tried moving my sim to the dorms in Britechester. The dorm he moved into loaded, but once he tried traveling to other lots in Britechester the 123 Error code came back. Also, I have no mods.
I'm not sure how to share my save file but am perfectly willing to if that would be helpful.