he say the callback is working, only the result is always error .
from the screen , the Paypal gateway send a completed payment status, and also a verified status for the post-back confirmation .
but i don"t know why blesta mark the it as failed !!!
the only reason that will mark VERIFIED status as error is if the "business" & "receiver_email" are not the same in the input and output . this data was cleared by you, so you can check them .
another test to do is replacing
case "completed":
by
case "completed":
case "verified":
...........
From my side , i never get 3 intries in a paypal log , only 2 , the impout and the output , the last log never i see it in my gateway logs, and i support the problem is come from it.