Every GP tool in untools calls this to determine if the tool can be opened.
def isLicensed(self):
"""Set whether tool is licensed to execute."""
standard = arcpy.CheckProduct("ArcEditor") in ("Available", "AlreadyInitialized")
advanced = arcpy.CheckProduct("ArcInfo") in ("Available", "AlreadyInitialized")
return standard or advanced
Because it is running under an ArcGIS Server context, this function is presumably returning `False`.
I'm not sure how Server Python is running on Linux (Wine?), but untools is only built on win-64. https://anaconda.org/Esri/untools/files
Even if the license check were changed to work on both Server/ArcGIS Pro, there's probably further work that would need to be done to ensure every tool works on linux-64.