Plane Simulation SITL Error

Hello,

Yesterday i could use Plane v4.0 Simulation but after the latest software update it started to give the error: “Failed to connect to SITL instance.” I asked some of my friends and they also told me that this error is new, yesterday there wasn’t an error like this. I checked Ardupilot and tried to solve the problem step by step but unfortunately i failed again because of the same mistake. There is going to be competittion in two days so i should solve the problem as soon as possible.

If someone could help me i will be thankful.