There are various reasons why you may be unable to add money. Please check and eliminate all the below-mentioned issues generally related to this:
1) Check to confirm that your bank account has sufficient balance.
2) Check with your bank if you have registered your card for online transactions, especially if you are using a debit card.
3) Check if you have already reached your monthly spending limit of your credit card
4) Check if your Boost wallet balance is reaching its limit. Basic Wallet has a limit of RM200, while Premium Wallet has a limit of RM1,500.
If all else fails, try another mode of payment. Otherwise, please share the following details (your phone number & date of transaction) by submitting a request via firstname.lastname@example.org. We're happy to help you out!