Today I attempted to enter my client player's gate to go to his client player. It did not work. The gate did nothing.

There are some natural ways for gates to not operate, such as when to destination gate exists, as dweb question was related to. I think what we need to do here is to have some way to convey to the player when this is the case for a player that's not teleporting.
The simplest solution is to just send a chat message to the player trying to go through the gate, but some other solution might be nicer.

Was their connection disrupted and are you sure that the person you helped enter has their own client player who has entered?

Hmm, looks like there's a message for the destination gate being destroyed, and a message for destination land not yet existing, but only the first one is actually being used.