System group failure in Google contacts

i cannot upgrade a folder in my Google contacts: it’s the COWORKING folder that i renamed “COLLEGHI” some time ago:

[Google Contacts] Creazione o aggiornamento cartella ‘’ fallita a causa del seguente errore: Cannot modify a system group.

On Google contact’s page i can find the right COWORKERS folder.

I tried to “repair” the Contacts’ folder in eM Client, but all the contacts disappared and they cannot be reloaded because of the error before.
And for the same reason I cannot delete the COLLEGHI folder in eM Client.

How to solve it?
Best regards.