My wife and I have a BDO savings account. When using their online banking, they send an SMS to a mobile phone number that you register on your profile with a one-time-pin (2-factor authorization) when you log in, and another one whenever you want to move money.
Last Thursday (1/21/21) I saw a message that they were doing system maintenance, and since that time I have not been receiving the transactional OTP messages, so I haven't been able to send money to GCash or anywhere else. After several hopeless interactions with their support staff via email, I figured that the problem may be with my registered phone number - it's from the US and I use it solely for receiving these 2FA messages from BDO and my other banks in the US.
So today, I switched my registered phone to a Philippine number (Globe), and voila, everything is working again. I did notice there is a new step in authorizing the transaction - they first send you a message asking you to reply with "SEND MONEY", then they send the OTP. So that confirms that they made changes to this process last week. Maybe something else was causing my problem, but I thought I should share my experience with you.
I replied to their latest support email with this revelation and suggested they raise the issue with their IT department if they want to keep their foreign customers happy. Not holding my breath.
Cheers,
-- Rich