Unable to select which of my 2 accounts to send from defaults to gmail

I have 2 accounts (lineone.net Which is hosted by talktalk and gmail. If I receive mail to lineone.net I am unable to reply using this address which is my main. If trying to make this the default message says both send/reply to be on but don’t see how to do this

Hi.

If you’re unable to send from your Talk Talk (Lineone.net) account in EM-Client, ensure you have the latest version of EMC installed > Release History | eM Client

Also check EMC settings are correct for Talk Talk >
https://community.talktalk.co.uk/t5/Articles/Email-settings-to-access-TalkTalk-emails/ta-p/2204399.

(As you probably know, Talk Talk recently upgraded its security settings to TLS 1.2. and many people on the Talk Talk forums have had similar issues).

This means that either the account doesn’t have an SMTP service, or it is disabled. Go to Menu > Accounts and click on the General tab for this account. Scroll down to Services and tick the SMTP service, then click on Save & Close.

If the account doesn’t have an SMTP service, maybe you imported it from another app. Best is to go to Menu > Accounts > Add Account and enter the email address in the automatic setup. That should setup the account correctly with both IMAP (for receiving messages) and SMTP (for sending messages). To set an account as default, it needs to have both enabled.