Error when calculating an FSI problem by preCICE and my solver

I am working on the FSI problem. I want to couple my solver with openFoam by using preCICE, and I have achieved that. But when I simulate the case of “perpendicular-flap” using my solid solver and openFoam, there is an error when t=0.8s.
solid solver:


Why this happened? Is the fluid or the solid wrong? Does fluid computation not converge? I need your help, thank you!

The problem seems to be in the solid solver, as can be seen in the warning, the displacement value of the two iterations is the same, you can check what went wrong by exporting the coupled grid data.
Export configuration | preCICE - The Coupling Library


Thank you very much! I will check it.