LattePanda 3 Delta red blinking and blue led but no boot

Hello,

My LP 3 Delta has been working fine till today. Now, when I try to boot after connecting to power supply with the standard adaptor, the following happens every time:

1 blue light turns on

2 green light turns on and very quickly off

3 red light starts blinking for around 10/15 times and then turns off

4 blue light remain fixed, but nothing can be visualized on my monitor (no hdmi output). Keyboard leds are on.

I tried the "hard reset" method and I tried to remove the RTC battery, both methods did not work.

Thanks in advance for your help.