The wireless caller is not available happens almost every day

For the past couple of weeks, I've been getting "The wireless caller is not available" message when I try to call someone, nearly every day. I haven't figured out a pattern, though it doesn't seem to matter where I am (like what state I'm in), whether I'm using Apple CarPlay or not, or what kind of connection I have (strong, weak, 5G, LTE). Sometimes, when I try the call again, it goes through. Sometimes it takes three or four tries. I'm running iOS 26 (beta) on an iPhone 15 Pro. I have cellular data on, roaming on, and Wi-Fi calling off. Any thoughts/ideas/help would be appreciated.