outgoing email not working

I have two comcast email addresses. I updated my OS to Ventura on my 2017 Macbook pro laptop this fall. My email was working fine for a while. But for the last two months, there have been issues sending emails, but both comcast accounts in Mac mail can always receive emails. First time I couldn't send out emails, a day later it suddenly started working again and I was able to send outgoing emails. Then two weeks later, I couldn't send any emails. I deleted the comcast accounts in my Mac mail and added them back in. I could again send emails. A couple of weeks later, same issue...couldn't send outgoing emails. I deleted the comcast accounts in my Mac mail again and then added the account back in. I could again send emails. I'm having the issue now where I can't send emails. I get no error messages; the emails just don't go out and aren't visible in the sent folder. I tried the same trick again deleting the comcast accounts in Mac mail and adding them back in, but this time I still can't send out any emails. I can receive emails. On another Macbook pro laptop we have, we use the same two comcast.net email addresses and that old laptop hasn't experienced any email issues at all. I'm desperate for some clear guidance on how to fix this. The comcast email accounts get the green light in the Connection Doctor, so they look fine there. For SMTP, I use my email address as both both the description and the user name as was mentioned in another post here. I use smtp.comcast.net as the host name. I have tried contacting Comcast technical support but they just kept tranferring me to the wrong reps for help...like they sent me to someone in billing, someone for phone issues, etc. They transferred me literally 5 times to people in different departments who don't offer technical support for Comcast email. It was just a waste of time. Any and all help would be appreciated. I've been working to try to solve this all day. Thanks!