I can reproduce the error with stage.obrunete.observatorio-municipal-brunete.org on a fresh install. I can resolve the error with the following at the top of the http block.
server_names_hash_bucket_size 128;
[If] server name is defined as “
too.long.server.name.example.org” then nginx will fail to start and display the error message… In this case, the directive value should be increased to the next power of two
– nginx docs
So, bumping server_names_hash_bucket_size up from 64 to 128 seems to resolve it.
Don’t worry about submitting a bug report. What we’ve figured out here is sufficient. I’ve started working on a Trellis feature to make server_names_hash_bucket_size configurable without having to modify Trellis core files. Time permitting, it would be an overhaul to Trellis nginx includes.