Depending on the nature of your problem there are a few possible ways of getting help with your problem.

Stack Overflow

Stack Overflow has an active community answering questions on both the bluebird and promise tags. If you are unfamiliar with Stack Overflow, do review the asking guidelines before asking a new question there.

Google Groups mailing list

The bluebird-js@googlegroups.com mailing list is the best place to ask any question that cannot be easily fit in the stack overflow question format.

IRC

You can usually get fast answers on the freenode.net channels #bluebird and #promises.

Gitter

If you are not comfortable using IRC you can also join the bluebird gitter chat

Github issue tracker

If you feel that your problem is caused by a bug or a missing feature that should be added, you should use the Github issue tracker to report it. However in any other case the issue tracker is not the appropriate channel.