Hello,
I was running a study on Heroku and all of a sudden I stopped getting updates on the data and I got the following message: 

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Server Error (500)
There are several ways to find the cause of the issue:

Delete the OTREE_PRODUCTION environment variable and reload this page
Look at your Sentry messages (see the docs on how to enable Sentry)
Look at the server logs

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I had collected about 600 responses previously with the same heroku settings etc. so it shouldn't really be about not having enough dynos, etc.

I currently cannot access the otree deployment dashboard. What is the best first step to take and minimize the risk of losing the data? I do have some emails from sentry I could share.

yes, check Sentry for the errors.

I'm getting the following error. The question is, why is it doing this all of a sudden, and why is it connecting to aws?:

OperationalError: connection to server at "ec2-3-208-74-199.compute-1.amazonaws.com" (3.208.74.199), port 5432 failed: Connection refused
    Is the server running on that host and accepting TCP/IP connections?

(17 additional frame(s) were not displayed)
...
  File "django/utils/six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "django/db/backends/base/base.py", line 213, in ensure_connection
    self.connect()
  File "django/db/backends/base/base.py", line 189, in connect
    self.connection = self.get_new_connection(conn_params)
  File "django/db/backends/postgresql/base.py", line 176, in get_new_connection
    connection = Database.connect(**conn_params)
  File "__init__.py", line 127, in connect
    conn = _connect(dsn, connection_factory=connection_factory, **kwasync)

OperationalError: connection to server at "ec2-3-208-74-199.compute-1.amazonaws.com" (3.208.74.199), port 5432 failed: Connection refused
    Is the server running on that host and accepting TCP/IP connections?

  File "django/db/backends/base/base.py", line 213, in ensure_connection
    self.connect()
  File "django/db/backends/base/base.py", line 189, in connect
    self.connection = self.get_new_connection(conn_params)
  File "django/db/backends/postgresql/base.py", line 176, in get_new_connection
    connection = Database.connect(**conn_params)
  File "__init__.py", line 127, in connect
    conn = _connect(dsn, connection_factory=connection_factory, **kwasync)

Looks like you are on the old version of oTree. You may be over the connection limit for Postgres. You can check that in the heroku dashboard. Otherwise I’m not sure why the database was refusing connections.