This is a question about apt, not RabbitMQ.
entry from /etc/apt/sources.list.d/* or /etc/apt/sources.list.
Or remove them all and repeat the
step from the [3.6.x] Debian installation guide.
FTR, Ross contacted team RabbitMQ off-list and
we concluded that there an incorrect apt source entry was previously added to apt, which failed installation. That’s how we know there was
an incorrect entry.
RabbitMQ releases starting with 3.7.0 are no longer distributed via
rabbitmq.com. Please use Package Cloud [1] or Bintray [2].