After an upgrade from an older version of Lime CRM, RabbitMQ may fail to start. This is caused by earlier versions of Lime CRM installing a malformed configuration file for RabbitMQ. This file was, however not used in that version.

Newer versions of Lime CRM does read that configuration file, which may cause RabbitMQ not to start. A Lime CRM upgrade never overwrites existing configuration files, therefore the syntax error is not automatically fixed.

Edit the file C:\ProgramData\Lundalogik\LIME Pro Server\RabbitMQ\rabbitmq.config

Change it from:

%% -*- mode: erlang -*-
%% ----------------------------------------------------------------------------
[
{rabbit,
    [
        %% Log levels (currently just used for connection logging).
        %% One of 'info', 'warning', 'error' or 'none', in decreasing order
        %% of verbosity. Defaults to 'info'.
        %%
        {log_levels, [{connection, error}]},
    ]},
]

to:

%% -*- mode: erlang -*-
%% ----------------------------------------------------------------------------
[
{rabbit,
    [
        %% Log levels (currently just used for connection logging).
        %% One of 'info', 'warning', 'error' or 'none', in decreasing order
        %% of verbosity. Defaults to 'info'.
        %%
        {log_levels, [{connection, error}]}
    ]}
].