If this helps, on the application logs in fly UI:
2023-08-16T09:05:30.199 app[e784eee6f396e8] ewr [info] [2023-08-16 09:05:30 +0000] [267] [ERROR] Socket error processing request.
2023-08-16T09:05:30.199 app[e784eee6f396e8] ewr [info] Traceback (most recent call last):
2023-08-16T09:05:30.199 app[e784eee6f396e8] ewr [info] File “/usr/local/lib/python3.11/site-packages/gunicorn/workers/gthread.py”, line 271, in handle
2023-08-16T09:05:30.199 app[e784eee6f396e8] ewr [info] keepalive = self.handle_request(req, conn)
2023-08-16T09:05:30.199 app[e784eee6f396e8] ewr [info] ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2023-08-16T09:05:30.199 app[e784eee6f396e8] ewr [info] File “/usr/local/lib/python3.11/site-packages/gunicorn/workers/gthread.py”, line 343, in handle_request
2023-08-16T09:05:30.199 app[e784eee6f396e8] ewr [info] util.reraise(*sys.exc_info())
2023-08-16T09:05:30.199 app[e784eee6f396e8] ewr [info] File “/usr/local/lib/python3.11/site-packages/gunicorn/util.py”, line 626, in reraise
2023-08-16T09:05:30.199 app[e784eee6f396e8] ewr [info] raise value
2023-08-16T09:05:30.199 app[e784eee6f396e8] ewr [info] File “/usr/local/lib/python3.11/site-packages/gunicorn/workers/gthread.py”, line 329, in handle_request
2023-08-16T09:05:30.199 app[e784eee6f396e8] ewr [info] resp.write(item)
2023-08-16T09:05:30.199 app[e784eee6f396e8] ewr [info] File “/usr/local/lib/python3.11/site-packages/gunicorn/http/wsgi.py”, line 346, in write
2023-08-16T09:05:30.199 app[e784eee6f396e8] ewr [info] util.write(self.sock, arg, self.chunked)
2023-08-16T09:05:30.199 app[e784eee6f396e8] ewr [info] File “/usr/local/lib/python3.11/site-packages/gunicorn/util.py”, line 287, in write
2023-08-16T09:05:30.199 app[e784eee6f396e8] ewr [info] sock.sendall(data)
2023-08-16T09:05:30.199 app[e784eee6f396e8] ewr [info] TimeoutError: [Errno 110] Connection timed out
2023-08-16T13:54:14.326 proxy[e784eee6f396e8] ewr [error] could not make HTTP request to instance: connection error: timed out
2023-08-16T15:08:37.308 proxy[e784eee6f396e8] ewr [error] could not make HTTP request to instance: connection error: timed out
2023-08-16T15:09:37.850 proxy[e784eee6f396e8] ewr [error] could not make HTTP request to instance: connection error: timed out
2023-08-16T15:09:52.681 proxy[e784eee6f396e8] ewr [error] could not make HTTP request to instance: connection error: timed out
2023-08-16T15:20:11.009 proxy[e784eee6f396e8] ewr [error] could not make HTTP request to instance: connection error: timed out
2023-08-16T16:29:17.944 proxy[e784eee6f396e8] ewr [error] could not make HTTP request to instance: connection error: timed out
2023-08-16T16:29:44.070 proxy[e784eee6f396e8] ewr [error] could not make HTTP request to instance: connection error: timed out
2023-08-16T17:01:08.277 proxy[e784eee6f396e8] ewr [error] could not make HTTP request to instance: connection error: timed out
2023-08-16T17:01:52.144 proxy[e784eee6f396e8] ewr [error] could not make HTTP request to instance: connection error: timed out
2023-08-16T17:02:05.945 proxy[e784eee6f396e8] ewr [error] could not make HTTP request to instance: connection error: timed out
2023-08-16T17:45:09.672 proxy[e784eee6f396e8] ewr [error] could not make HTTP request to instance: connection error: timed out
2023-08-16T17:50:10.795 proxy[e784eee6f396e8] ewr [error] could not make HTTP request to instance: connection error: timed out
2023-08-16T17:55:58.964 proxy[e784eee6f396e8] ewr [error] could not make HTTP request to instance: connection error: timed out
2023-08-16T20:58:05.455 proxy[e784eee6f396e8] ewr [error] could not make HTTP request to instance: connection error: timed out
2023-08-16T21:01:46.925 proxy[e784eee6f396e8] ewr [error] could not make HTTP request to instance: connection error: timed out
2023-08-16T21:04:24.242 proxy[e784eee6f396e8] ewr [error] could not make HTTP request to instance: connection error: timed out