generated digital code

Hello!

Today I tried to login into my account after months offline due to work and study reasons, and I couldn't. I had just downloaded the client again this morning, and have changed nothing in the folder (so it is as is, as downloaded from this website), but when I tried to log in and I introduced my password, a pop-up window called "authenticator code" appeared and asked me for a "generated digital code".

Any ideas? I have played in this server for years and it never ever asked me for anything like that.

Thanks a lot!

Edit: I could enter after deactivating my two-factor identification, but isn't there any way to have the two=factor and still play? It never asked me for any such code before.