05-28-2020 03:34 PM
What mode are you using? light-of-sight or radio signals?
How are you controlling that speedlite? Via a slave flash, or ST-E3-RT radio controller?
Once we have more details, we can then help to troubleshoot.
05-31-2020 05:24 PM
The led indicates red only. Not green. Hence not firing. Also an exclamation symbol appears on display along with ettl
I don't know why it's not firing, but I think you're misinterpreting the LED. Check your manual. IIRC, red means that the unit has reached its full firing power, while green means that it hasn't. (Yeah, I know that's counterintuitive, but it is what it is.)