Before posting a bug report on the forum, have a quick here to make sure it it isn't one of the common, known issues. If you're not comfortable with working on beta releases, you can always switch back to the normal release via the on Steam properties of X Rebirth.
Problems in unmodified (AKA "vanilla") games
The place to post feedback involving problems with the currently released Rebirth version and/or the current Beta patch or update is the Beta forum here, taking into consideration the instructions here.
For X Rebirth issues of a more technical nature, such as relating to system requirements or installation issues, please see the Technical Support forum here.
Problems in modified games
If you experience problems in saves where either now or in the past extensions (AKA "mods") or save edits were used, please try to reproduce the issue in new, unmodified game and report as per the above. If the problem only appears to occur in a modified game, you can try to narrow down the cause by sequentially turning off extensions until it might go away. If you need a quick injection of Credits to help you narrow things down, you could use the unmodified save here and sell some assets.
If successful in finding the cause, you can then ask for help in the thread relating to the extension or save edit. If unable to work out what extension may be the cause, you could try asking in the thread of one of mods that people have posted in recently but it's a bit of a long shot. You can find information on where threads about extensions can be found here.
Please note that even after turning off or uninstalling an extension, or reversing a save edit, the save will still be considered modified.