The same thing happened with my 2015 and ultimately VW replaced the charging port on the car. The solenoid that retracts the locking pin would occasionally not retract but luckily I could push the pin back using a screwdriver. This work-around was fine for a couple of months but eventually the solenoid completely failed and prevented the car from charging. Luckily I reported the issue during the 30K service and they didn't find any issues, so when it completely failed and I had 38K on the car, they still did the fix under warranty. It took them about a week and they had to drop the battery in order to access the charge port, so it would have been very expensive.