SIM7600EI not responding to File System AT Command

Hello everyone,

I am working on SIM7600EI 4G LTE Modem and modems firmware version is LE11B12SIM7600M22.

Recently I was working on SD Card file system of Modem and I was able to work with “C” directory which is a default directory, I also wrote the data in the directory and read the data from the directory but when I was trying to change my directory to other directory like “D”, “E”, “F” the modem was not responding at all. I am unable to figure out why this is happening its not even giving error.

I will really appreciate any suggestion on this.

Following is the test log

AT+FSCD=C:

+FSCD: C:/

OK
AT+FSLS

+FSLS: SUBDIRECTORIES: 
SIM
SIM7600E
SIM7600E-H

OK
AT+CFTRANRX="C:/SIM7600E/Testingg.txt",10

>123456789

OK
AT+CFTRANTX="C:/SIM7600E/Testingg.txt",10  

+CFTRANTX: DATA,010
123456789


+CFTRANTX: 0

OK
AT+FSCD=D:AT+FSCD=E:AT+FSCD=F: