Unlock Device Tool Unknown Network error

[Avijeet]

Model Name: Asus Zenfone 2 Laser "ASUS_Z00LD"
Firmware Version: WW_21.40.1220.2196_20180308
Rooted or not: Not Rooted
Frequency of Occurrence: Always
APP Name & APP Version: Unlock Device Tool
Android Version: 6.0.1
Dear Asus Team,
I'm an Asus Zenfone 2 user facing some problems with unlock device tool. It says an unknown network error which I provide here with an image. For kind information, I have unlocked bootloader once through this app. In recent days, I rebooted my phone and this time the unlock device tool showing me the message of unknown network error. Please regarding this, try to solve my problem as early as possible.
Thanks.

[Christine_ASUS]

Hi friends
For ZE550KL, there will no longer have any maintenance. Sorry for any inconvenience this may cause. Thank you for your understanding and support.

[vtrguimaraes]

Yeah, thanks for nothing. What a terrible company. "Thank you for your understanding and support". Thank you for your incompetence, gosh