Push notifications ionic v1(latest) API endpoint sometimes doesnt work


We collect self the device tokens through an own API where it is send through.
Except when we send a mass push notification through the REST API service endpoint,
with some of 1700 device tokens (e.g. android and ios) in an array,
sometimes the message is recieved and sometimes nowhere.

When i retreive GET to the rest api at the notification_uuid:/messages endpoint

i receive only in around 30 responses from tokens…

What could be the problem that sometimes de message gets through and sometimes nog?
Is there a limit on MAX DEVICE TOKENS that i give with the json in de REST CALL ?

I could really use some help…
I mailed to ionic and didnt got any response…


Even I am getting the similar issue.
Were you able to figure out cause behind it?