LM1200 - SMS Alerts

I've been using the Netgear LM1200 as 4G failover since May 2025 with everything working perfect.

Every month I perform a test to confirm failover and sms alerts still working as usual, however for the past few days and several tests I'm not receiving the text alert for any event. When logged into the LM1200 settings page, a popup does indicate message was sent - just not receiving text notification at any number I assign.  Any tips or feedback would be appreciated!!