Can you post your lib/application.ex here? Judging by the error alone, there is a problem at absinthe/lib/absinthe/subscription.ex at v1.4 · absinthe-graphql/absinthe · GitHub so it’d be helpful to see how you define the children for the supervisor.
According to the guide for version 1.4 it should be like this:
[
# other children ...
supervisor(MyAppWeb.Endpoint, []), # this line should already exist
supervisor(Absinthe.Subscription, [MyAppWeb.Endpoint]), # add this line
# other children ...
]
On the master branch they’ve added the child_spec approach but note that the guide doesn’t include it. I’d try something like
[
# Start the Ecto repository
MyAppWeb.Repo,
# Start the endpoint when the application starts
MyAppWeb.Endpoint,
{Absinthe.Subscription, [MyAppWeb.Endpoint]} # <-- note this is different from the guide
]
since in v1.4 child_spec expects a list, not a single module atom.
