Hi every one, hope someone can help me. I have a special mail account: contact@c-serp.fr The incoming server is managed by my Synology NAS server (MailPlus server), the identifiers are Incoming server : - protocol: imap - hostname: c-serp.fr - Port: 993 - Connection security: SSL - authentication method: normal password - username: contact@c-serp.fr - Pwd: ------------------- Outgoing server : - protocol: smtp - host name: smtp-relay.brevo.com - Port: 587 - Connection security: STARTSSL - authentication method: normal password - username: XXXXXXXXXXXXXXXX@smtp-brevo.com - Pwd: -------------------- All these settings work perfectly on outlook 2021. But on Thunderbird, nothing works. Why is this? Any suggestions are welcome Ucan. Translated with DeepL.com (free version)I have an email account