Curl: invalid value passed for authtoken

Curl: invalid value passed for authtoken

Hello there

I signed up today at zoho.com and tried to generate few invoices as a test. I generated authtoken using link provided in the documentation and called following command:

"curl https://invoice.zoho.eu/api/v3/invoices?authtoken=9fb16****"  (hidden for security)

I tried both on bash on linux machine and cygwin command line in windows. Unfortunately, zoho returned: {"code":14,"message":"Invalid value passed for authtoken."}.
I tried few times generating new authtoken, deleting old ones, but without success. Every authtoken was visible in the "Active Authtokens". 

Thank you for response in advance.
Best regards