I can't create my third model. Please unlock!

Hello! I really love your work. I have the following problem: I created two models of mine without realizing it, because the rendering of the first model was not displayed correctly. So - with the same set of photos - an identical model was created twice, which I did not want at all. I tried to delete a model, that worked, but now I don't have the possibility to calculate a third model anymore, I only have two models and can't create a third one. Can you please unlock a model for me? Thank you and best regards! Lars