Please tell us some basic information before asking for help:
Model Name: ZS630KL-2A005EU
Firmware Version: latest Android10: 17.1810.2011.183
Rooted or not: No
Frequency of Occurrence: Always
APP Name & APP Version (If your issue relates to the app): Both with unlock tool version 18.104.22.168 and 22.214.171.124
In addition to information above, please also provide as much details as you can, e.g., using scenario, what troubleshooting you've already done, screenshot, etc.
The app says (translated) "Unknown network error. Please wait and try again later "
Is the ASUS unlock server unavailable at the moment? (This seems to happen quite a lot, as this issue appears rather often when I search for it.)