There are some situation when your Yocan UNI device flashing 5 times.
#1 The battery don't install 510 oil cartridge.

#2 The oil cartridge has some connection error.

Here are some tips:
Regularly clean the 510 thread adapter.
Make fure cartridge and adapter connected firmly.
If still can't fix this Yocan UNI blinking 5 time issue, please try to install a brand new oil cartridge.
Or leave a comment below.