Harvesting Twitter with R - Account Confusion


I have created an app for R to access Twitter in my account. When I receive the url to get the authorization number, a very confusing thing happens. If I login with my account and enter the number I get, I get an authorization required error, BUT if I login under a different account which is in no way connected to mine and enter the number I get, the search works fine. Explain that to me, please.