Interlocking Towers - Very Basic ?

I could not get the initial EIT window to open after trying two recent towers. I had worked with EIT before but no luck this time. I opened an old route that was for testing EIT and there the Invisible tower opened the first menu ok. Then tried invisible tower on my route and ok. Tried a random tower and it was ok. I just hit two duds. If I knew how I would delete this message.

Possibly not the cause in your case but I had a similar experience with an EIT until I realised that I was trying to open it through a tree that was so close to the camera point of view that its presence was not obvious on the screen. I moved the point of view slightly and the EIT menu opened.