Specifically to a Celcom Postpaid user only, there are various reasons why you might not be able to make a postpaid bill settlement
1. You might have insufficient balance in your Boost wallet. If so, please top up your Boost wallet first before attempting your bill payment
2. There might be an error in your mobile operator's systems at the moment, do try again in an hour or so.
If the issue persists, please submit a request email to us at firstname.lastname@example.org