Yep headlight.
Pinalitan for free (May 2019 kinabit) pero same issue. Sabi nung cashier uli, di pa pumapasok load.
Pero yung last na nakausap ko sa toll booth, inayos na daw niya.
I think more on system glitch vs physically defective yung tag.
Then I tried again kanina, ayun gumana na uli and nabawasan na yung balance ko sa website.