Hi,
I'm sorry I don't speak or write Italian, but hopefully this is helpful to you. I encountered the same problem and discovered a workaround. In the files (where site_root is the root directory for your Joomla installation):
site_root/components/com_linkymap/helpers/linkymap.php
site_root/administrator/components/com_linkymap/assets/js/linkymap.php
look for calls that start with
google.charts.load ('current', ... and replace
current with
49, so the calls look like
google.charts.load ('49 ', ...
Also, delete the directory
site_root/cache/mod_linkymap
Reload the page (s) where you saw the error, and the Linky Map module should load normally. We have an active subscription to Linky Map, so I reached out to JoomUnited to report the problem, which appears to be related to a recent (April) update to the Google Visualization API. The changes above will load a specific (the previous) version (49) of the Visualization API.
https://developers.google.com/chart/interactive/docs/release_notes#official-releases