@Pierre-Briec I was able to sucussfully send using a gmail account/smtp by setting up an 'app password' in the gmail account settings. You need to have 2FA turned on for the account. Easiest way to find it is to use the search function (type app, and then select app password from the options which auto populate), otherwise its in the 2-step verification menu (Security....how you sign in 2 Step... app PW at the bottom). Once you get to that screen its very straightforward, add app, name, and it will give you a 16 Char PW which you can use in mail-transport. Hope this helps.