Currently, we have an ongoing investigation about customers being unable to receive an SMS for the OTP or verification code.
Our engineers are currently working on this to sort it out as quickly as possible. Since they are working on this internally, please know that we cannot provide a turnaround time regarding their efforts.
Moreover, to ensure you'll get an update about the resolution status, I recommend contacting our QuickBooks Support Team. This way, they can add your company file to the list of affected users and provide this investigation number for easy tracking: INV-92746.
Since you’re unable to reach them out within your company file, you can contact them by going to this page and providing a short description of your contact reason. After that, follow the onscreen instructions: Contact QuickBooks Online Support.