Deepl plugin on Tradus Studio 2021 - Authorisation failed. Please supply a valid API Key

I work with Trados Studio 2021 and tried to activate my Deepl plugin, providing the API Key. As soon, as I start typing the API Key, the system returns the message "Authorisation failed. Please supply a valid API Key", without giving me the time to insert the whole key.

The API Key is valid, because it is the same I use for annother CAT. Should I ask for a new API Key?

Thank you in advance for your responce.

Marco Pedretti