RROR: No valid DW gradient scheme provided or present in image header

Hi experts,
My name is Qiuyi. I tried to use MRtrix3 to preprocess the DTI data of rat brain. After I did dwifslpreproc, I got dwi_preprocessed.mif successfully. But when I used this dwi_preprocessed.mif to do the next step using dwibiascorrect, it showed that [ERROR] No valid DW gradient scheme provided or present in image header. I used mrinfo to check the dwi_preprocessed.mif, there was no dw_scheme information. But the other *.mif files generated before the dwifslpreproc step had the dw_scheme. It seems that during the preprocessing using the dwifslpreproc, the information of dw_scheme was lost. I don’t know how to solve it, could you help me with that. Thank you very much!

here is the step of dwifslprepro (successful):

here is the result of mrinfo dwi_preprocessed.mif (without dw_scheme):