I'm sending emails on Mac mail, with Yahoo/ATT, and while the Mac Mail shows they were sent, the recipients are not receiving them. This has been an off and on problem for two days. Any ideas?

My emails are not being received. I have a 2020 MAC Book Pro, Sonoma 14.1, and I'm using Mac Mail with ATT/Yahoo. The email account shows that the messages in the sent folder and I'm not getting any error messages, but the recipients are not receiving the emails. This has been an off and on problem for two days, sometimes they are received, most often they are not. The recipients have different email programs and are not having trouble on their end except for my emails. Any ideas?