My problem solved. just go to this link.
XT1723 Baseband Unknown/ IMEI Null/ No Service/ No Sim Card/ Emergency Call only Fix
Phone original condition was Unknown baseband with Null IMEI.
Steps to fix this Issue:
I Repair baseband with CM2 MTK 2.06 using Secure boot DA file but still baseband unknown.
Flash Stock ROM with SP Flash tool using custom DA file "format all+Download" and baseband fixed successfully and Sim card detecting but this time IMEI is "invalid" or "000000000000000"
I tried Repair Original IMEI (which is written on the backside of Phone) with MauiMeta tool but it requires "DB" file from inside phone or from Firmware but DB file not found in Phone and Firmware.
I searched on many forums on the internet for correct matching DB file for XT1723 but no file found.
After too much struggle, finally, I got DB to file for XT1723.
After writing Original IMEI with MauiMeta, original IMEI restored and phone working perfectly with networks, RIL, Mobile Data and so on.
useful Links:
DB file XT1723
DA_SWSEC_Moto c plus xt1723