On 6th Feb 2026 a professional set up Thunderbird [149 I think] on my Desk top computer, running Windows 10, with 2 email addresses. Last week I found I could receive emails on both, but not send on either. I know the passwords for both the addresses, but even if I put them in when asked, I still could not send. Then I found I was not receiving e mails on either address as well. I am 87 and may have changed something important, in an effort to find a solution, as last Friday [27th March] thunderbird crashed. I sent the report to thunderbird. Yesterday I received the previous day's emails and current ones. Today [29th] I am receiving, but not able to send again, My email default is set as Thunderbird. For many years I was with Plusnet, but recently I had to transfer to Greenby. I checked their Web mail when I was not receiving emails and they were on their Server. I can make simple changes in Account Settings eg Port, Outgoing Server, Security.. Is there a simple solution or should I call the Professional again? Thank you.