How do I get my phone out of a bootloop?

[AC Question]

my phone is stuck on bootloop and has a problem with his cache

My phone somehow got stuck in a boot loop and I can't fix it. I don't know what to do. I cant get pass the start up animation no matter what I do.

I've tried the fast boot commands to flash and keep getting the error (i dont really know alot about flashing and never done it before but the that what i found suggested in the web..)

FAILED < remote: flash write failure >
I've tried the flash-all.bat file, but the lock state goes back to LOCKED when it reboots the device and I get the error

not supported on lock device
I can unlock the device when I type fastboot oem unlock, but if the device is restarted it goes back to LOCKED.

I've tried recovery mode and I see the below statements:

E:failed to mount /cache (Invalid argument)
E:Can't mount /ache/recovery/log
E:Can't open /ache/recovery/log
E:failed to mount /cache (Invalid argument)
E:Can't mount /ache/recovery/last_log
E:Can't open /ache/recovery/last_log
E:failed to mount /cache (Invalid argument)
E:Can't mount /ache/recovery/last_install
E:Can't open /ache/recovery/last_install
E:failed to mount /cache (Invalid argument)
I've tried wipe data/factory reset

--Wiping data...
Formatting /data...
E:failed to mount /cache (Invalid argument)
Formatting /cache...
E:failed to mount /cache (Invalid argument)
E:Can't mount /ache/recovery/log
E:Can't open /ache/recovery/log
E:failed to mount /cache (Invalid argument)
E:Can't mount /ache/recovery/last_log
E:Can't open /ache/recovery/last_log
E:failed to mount /cache (Invalid argument)
E:Can't mount /ache/recovery/last_install
E:Can't open /ache/recovery/last_install
Data wipe complete
E:failed to mount /cache (Invalid argument)
E:Can't mount /ache/recovery/log
E:Can't open /ache/recovery/log
E:failed to mount /cache (Invalid argument)
E:Can't mount /ache/recovery/last_log
E:Can't open /ache/recovery/last_log
E:failed to mount /cache (Invalid argument)
E:Can't mount /ache/recovery/last_install
E:Can't open /ache/recovery/last_install
E:failed to mount /cache (Invalid argument)