Hi… In the past, this has turned out to be due to it trying to create the builder in the region closest to you, which is bom. (You can deduce that from the -bom suffix of the request ID that you posted.)
There’s an environment variable that you can use to override the default builder region, although the following instructions use Bash syntax:
https://community.fly.io/t/region-cannot-host-your-machine-fra/23071/31
(You may also need --build-depot=false these days.)
Hope this helps!