Problem solved by setting, in spectrumgtw probe configuration, the Landscape to name and not to handle:
- open admin console
- select spectrumgtw, clcik on ... and click on Configuration
- in 'Spectrum Selected Landscape' put the name of the landscape (do not use the handle)
The above is confirmed by the documentation, in "Deploy and Configure the Probe" section inside "spectrumgtw AC Configuration":
Spectrum Selected Landscape: Specify the SpectroSERVER under which UIM-managed device hierarchy is created/displayed in the OneClick view.
Note: When the spectrumgtw probe is upgraded to 8.65 or later, you must provide the landscape name (not the landscape handle, ex 0x10000000) in the Spectrum Selected Landscape field.