If you had an old login cookie in your browser cache, you'll probably still be able to post from the clearnet or .onion site for as long as that cookie persists and is valid, or until we proactively invalidate or otherwise neuter non-i2p cookies.

However, it shouldn't be possible to login or signup from anywhere other than ramble.i2p. This is by design to minimize abuse and the concomitant moderation workload, and to encourage I2P adoption.