Solvation free energy failed

Dear All,
I want to use Forcite to calculate the solvation energy. I took the structure from the last MD trajectory frame. I can't finish the calculation by selecting "ALL" contributions, but it ended with an error. Then I calculated the sorption energy with 3 steps, I was able to finish the "Ideal" and "Electrostatic" calculation, but with the "van der Waals", I finished with the following error:

An unphysical integration step (>100 Angstroms) has been detected.

But I've already ran geometry optimization, about 10ns NPT and NVT dynamics on it. I also tried to increase the equilibration steps to 50000, but I got the same error.

Any suggestion would be appreciated!

Regards,
Jingjing Bu