Thanks. I enable encryption by modifying fstab.qcom file manually. Now the encryption works.
(I also checked the thread you give, and create my fencrypt.zip for MIX2S. Maybe it can be used for the next time)
Thanks a lot! I have tried many methods in about 2 days and finally failed. Now I succeed to encrypt it with your help.
My device is MIX 2S and (with MIUI.eu beta version MIMix2S_20.1.21_v11-10, not stable version). Modification to fstab.qcom works well.