What did you check exactly? The exhaust hose, or the trap on your drier that pulls out?

If there is water in your hose you are not removing the air fast enough to avoid condensation. If there is no lint it might be due to pressure drop (friction loss) because of duct length or other blockage.

I'm assuming if your clothes are getting dry it's probably not a blockage or total failure of the fan but that the fan isn't running long enough to extract the last bit of humid air all the way back (either straight up or not long enough to overcome friction losses in the hose).