>>2870596 overwatered, it's dying of root rot. You need to re-pot it into some looser potting soil with pearlite for additional aeration and in a pot with good drainage. Right now you have an anaerobic zone that is allowing root rot bacteria to thrive and destroy your plant's roots.
>>2870604 >I haven't watered it in 2 weeks What is your drainage look like? are there holes in the bottom of the pot? When you moved it indoors, did you stop up the drain holes or something else to prevent it getting your floors wet?
>>2870608 This pot has holes on the botton, small rocks and then dirt mixed with perlite. When water collects on the bottom I drain the "dish" that is sitting on between the floor and my pot.
>>2870614 Definitely re-pot it. When you do, check the roots. Cut out anything slimy. It sounds like your pot has good drainage. So that leaves your soil. Well draining soil should be ok in a pot that size. But if mango's handle transplanting/repotting well, definitely go smaller until it's re-established itself. Otherwise, add more perlite to your soil to try and improve your drainage.