I have recently had to have my computer operating system restored. I have a Windows 10 Pro 64 bit machine. My broadband provider is Grande Communications whose new name is Astound. Anyway, I cannot get my account (setblack@grandecom.net) to send or receive emails once I reloaded Thunderbird onto my machine. It is frustrating as the dickens as IMAP Server and SMPT Server both tell me that the certificate is not valid for my address/provider. I have put in the correct ports for both servers according to the information provided by Astound for users in Texas (I live in Austin). I suspect that my provider is the source of this situation but I am bound and determined to find a solution as I have used Firefox and Thunderbird for a good while. It seems like I have had similar problems connecting to GrandeCommunications in the past. I can confirm security exemptions and check the box for Thunderbird to remember this confirmation. I must have figured it out at one point as I was using these programs till my machine bluescreened. Thanks for any help and guidance you could pass on to me. I can check for your response via Webmail...