Had a similar issue, did 2 things to resolve it:Oh I was looking at the pi_grafana_1, pi_teslamate_1, etc.
If I look at syslog (var/log/syslog) nothing much interesting shows up - see logs from around the time I tried to access 3000/4000 and couldn't access.
View attachment 791983
Increase the swap size to 2GB(2048), I used this answer:
How to set up swap space?
Raspberry Pi has only 256 MB of RAM, so I would like to use swap space (either on SD card or attached USB storage). How do I set it up?
raspberrypi.stackexchange.com
I also got a high performance SD card as I don’t think my original was appropriate for the amount of io needed to run TeslaMate and the additional swap space strain. This one to be precise: