TC75X -> OS Update fail -> FTP Connection not open !

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Hello all,

We have a lot of device TC75X under android 6, i would like to upgrade to android 7.

For this, i have downloaded the FULL IMAGE and place the zip file into the device -> /sdcard/AT_NN_FPU_AOSP_49.00.ZIP
I have reboot the device.

With stage now in version 3.4.0.1002 , i have create a new profile with mx version -> 6.0
Click on create new perform OS Update and fill all field:
- name -> OSUpgrade
- device already connected
- full os update
- file present on device ? Yes
- existing zip file on device: /sdcard/AT_NN_FPU_AOSP_49.00.ZIP

Opens stage now on device and scan barre code but every time i have an FTP Error -> file manager ftp client cannot connect to the ftp server !
original error message: query error, reason-FMC Couldn't connect to server : xx.xxx.xxx.xxx and port 21 …

Someone can help me ?
I would like to update the device with stage now of course because we have a lot of device to do …

thanks a lots
christophe