Me too, got 2 BT failures during the last weeks after the last app-updates, I can see it luckily very fast when checking my HomeAssistant screen.(HA on a RasPi5 connected via BT) 
The only chance to get the BT connection back to work is shutdown and restart the system. 
Sadly, all my connected devices has also a reboot which is not so good for the fridges and router…
Luckily the last weeks were without any problems, hopefully it will not happen in our holiday next month. (No one is here to fix the problems…)
System and Software are actual on my EP500Pro
Hi @BlueTobi, Thank you for sharing, and we’re glad to hear that the issue has finally been resolved.
Generally speaking, we recommend that customers re-download the app, upgrade all firmware to the latest version, and restart the Bluetooth on both the phone and the device. This is very helpful for Bluetooth connection issues.
Hello back @BLUETTI_CARE, I´m not sure that the problem is solved.
I did nothing else than resetting the EP500Pro, my App and hardware are actual as far as I know.
So I have no other choice than installing a safety switch for the bluetti crashes. If the device failed and I´m not at home, the switch will change the AC output to grid.
Offgrid Switch
The EP500Pro has priority, then the grid if it fails.
Hi @BlueTobi, I am sorry for the misunderstanding.
May I have your EP500PRO’s SN number and current firmware version?
We will check if there are any new firmwares does help.
Thanks for your help, you got a PM from me… 
I have had this same problem with my new Elite 200 v2. Sometimes it will not connect with wifi, which is set as my defult connect, and I have to go to Bluetooth
which then connects. I think I have solved the problem for myself. I have iPhone 11
In the Bluetti app go to settings, shut off the homepage display, which I had on to make it quicker to connect. But when I have this on it does not agree sometimes with my iPhone. Since I shut this off I have been connection flawlessly to either my Elite 200 or my Charger 1.
