Hopefully one of our bonsai experts will come by, but in the meantime, I am going to guess over-watered and in bad soil.
For some reason bonsai trees seem to be frequently (usually?) sold in heavy, organic soil that is all wrong for them. I suspect it is because it holds moisture so much longer, the trees can survive being shipped or not well cared for in the store without drying out so much.
Proper bonsai soil is very gritty, mineral, loose, free draining. Here's an article about bonsai soil:
You need to repot your tree in to good bonsai soil, which can be ordered on line if you can't find it locally.
And bonsai should never be watered on a schedule. They are watered when they need it. How many days that is between waterings varies with season, temperature, how fast they are growing, etc. With the moisture holding soil, daily watering is almost certainly too much. Here's an article about how to water your bonsai:
Use the chopstick method to know how wet/dry your soil is. Water thoroughly when it needs it, until water is running freely out the drain holes and don't water again until it is starting to dry out a bit.
Have you been fertilizing your tree?
Here's a thread with general bonsai care tips. https://www.helpfulgardener.com/forum/vi ... =36&t=1479
If you are serious about wanting to get in to bonsai as a hobby, then you need to do a lot more reading and understand what you are doing.
Welcome to the Forum!
Keep us posted about how your little tree progresses and whether you are able to save it.