I do not know what plant you have, but looking at it, your soil looks rather thick and dense. The leaves and stems indicates to me it has succulent properties (holds water on the leaves and stems), so it needs to have a more airy, porous media, to allow better airflow at root zone and not keep it too moist than needed. Plants roots gets compromised and rots away and manifests it by showing through the growth of the leaves, usually when overwatered edges turns brown, showing it is not able to drink up properly, and is ending up using its reserves remaining on the leaves, slowly drying them out and killed in the long run.
Try to improve your media, mix in some more pumice or perlite to lighten it up. Do not apply fertilizers, do not block drain holes with rocks and try to position in an area where it gets lots of bright light.
