Q: Is XigmaNAS DLNA certified or compliant?
A: DLNA is a set of non-open industry standards. It is prohibitively expensive, redundant, time consuming and difficult to submit XigmaNAS to the certifying standards body and for this reason we will probably never achieve certification.
Having said that, XigmaNAS uses many of the programs, protocols and methods defined by DLNA so it may work just fine for most DLNA devices, others may need special settings or tweaks to get working and some may not work at all.
Of prime importance is that your media files be DLNA compliant and that the manufacturer of your device has really adhered to the DLNA standard. If you have a problem with your DLNA branded device you should first read the documentation, limitations and troubleshooting guides that came with it, the manufacturer is best positioned to tell you if it works with Open Source software (like XigmaNAS) or not.