blowing-up with ' REASON: KEchar = NaN, PEchar = NaN' report

[cheng_dada]

Hi, good day for everyone.
I was running a climate state case recently, and after five months of running the model,the model blow up with the 'REASON: KEchar = NaN, PEchar = NaN' report。This is a nested grid model,
I've been searching the forums for answers to this question, and some people say it has to do with time steps.
Time-Stepping parameters as follows

5895969d178c3f23187a323773e7d09.png (12.24 KiB) Viewed 4437 times

The Vertical S-coordinate System and resolution of the two grids as follows
Grid 01

Grid 02

I have tried to change the time step to 60 and this error still occurs
I also checked my Climatology File and Boundary File, I didn't find mistakes。
The following is the error report , and running log.I hope you can give me some suggestions on how to solve this problem.

a_dt30.dat

(12.59 MiB) Downloaded 166 times

[qwdy]

Hi, do you find what cause the error "kechar=nan" or how to fix it? I'm encountering the same error.