Adding an airport now says The airport should be in the same zone as the airport declared previously

I added an airport that was missed, saved my work and then tried in the sim to see if it worked, all good. Now I want to go back and add taxiways and buildings but when I open it I get the following message “The airport should be in the same zone as the airport declared previously”. Any idea how to fix this?

I had the same issue. I found the ICAO code I was using was inthe meantime added to the SIM by another add-on (or by the SIM itself because of an update)

Try changing the ICAO code of your airport

Makes sense, this was an airport that I added. I wanted to add to it, taxiways, buildings,etc. What I will try to do is remove it from my community folder so that it isn’t in the sim anymore. I will add it again when I am done.