i\'m trying to call an api in my application i\'ve the following url template
test-test.domainname.com/feeds/json/v3/attribute/attribute
In my case, my base url contained space character. (eg. http://myapiname.azure webservices.net )
http://myapiname.azure webservices.net
I fixed this Error by removing space in my base URL.
Illegal URL Exception in retrofit is triggered when your passed url is not really existed or not fix with url standard.