Yeah, this one's common. Your cups or the infuser are cold.
First, warm your cups. Rinse them with hot water using the machine's hot water function. If the infuser has cooled down because it's been 2-3 minutes since the last coffee, you need to warm it directly. Press the rinse button before making your next coffee.
If that didn't work: Check the temperature setting on the control panel. Make sure it hasn't been accidentally lowered.
Heads up: For the hottest coffee, always preheat the cup and don't let the machine sit idle for more than a couple minutes between brews.