Have you tried deleting both directories – _build and deps – after upgrading Erlang?
dimitarvp
rsshek
D4no0
Currently the erlang AMQP client (and subsequent dependencies) don’t support OTP-27, the only option is to downgrade to OTP-26.
Here is the official link: Erlang Version Requirements | RabbitMQ
PS: I think there was somewhere a more detailed explanation on what it specifically breaks, but I cannot find it now.
4