iPhone 17: TeleMed call connection error. Not sure which iphone settings may have a problem...

I have an iphone 17. I am trying to have a telecall with my doctor. His office sent me a link to the telecall via a text. It is a "TeleMed" link. So, when I click on the link, it takes me to this website, where I can choose "join meeting." When I click on the box that says "join meeting," I get an error message: "There was an issue connecting. Please try these troubleshooting steps then RELOAD this page." It continues to give me 4 trouble shooting steps - like check your internet connection, check your security settings, make sure your browser can access your camera and audio devices, etc. Can someone tell me how to access my security settings? And what they should be set at? I have just downloaded the most recent Apple software update a couple hours ago, so it is not my version of software. Thanks for any advice. I appreciate it. By the way, the doctor's office sent me the link as a text and also in an email. I get the same error message by clicking on either link. Thx.