Cannot send a message from the desktop client (SMTP connection failure: Unexpected greeting)

[Aroogi]

• Operating System (Linux/Mac/Windows/iOS/Android): Linux
• Delta Chat Version: 1.46.5 (git: flathub)
• Expected behavior: SMTP successfully connects
• Actual behavior: Not being able to send any messages. Error in the connectivity tab. Outgoing Messages: Error: SMTP connection failure: Unexpected greeting: "220-wn09.webd.pl ESMTP Exim 4.96.2 #2 Sat, 24 Aug 2024 09:58:17 +0200 \r\n".
• Steps to reproduce the problem: Turning on delta chat and trying to send all pending messages.
• Screenshots:
  
• Logs:

2024-08-24T07:58:18.217Z	main/menu             	INFO	""	"rebuilding menu with locale en"
2024-08-24T07:58:18.229Z	core/event            	INFO	""	1	"src/scheduler.rs:814: SMTP fake idle interrupted."
2024-08-24T07:58:18.230Z	core/event            	INFO	""	4	"src/imap/idle.rs:86: INBOX.DeltaChat: Idle wait was interrupted"
2024-08-24T07:58:18.232Z	core/event            	INFO	""	4	"src/imap/idle.rs:86: INBOX.Sent: Idle wait was interrupted"
2024-08-24T07:58:18.233Z	core/event            	INFO	""	4	"src/scheduler.rs:814: SMTP fake idle interrupted."
2024-08-24T07:58:18.234Z	core/event            	INFO	""	4	"src/imap/idle.rs:86: INBOX: Idle wait was interrupted"
2024-08-24T07:58:18.235Z	core/event            	INFO	""	1	"src/imap/idle.rs:86: INBOX: Idle wait was interrupted"
2024-08-24T07:58:18.236Z	core/event            	INFO	""	1	"src/imap/idle.rs:86: INBOX.DeltaChat: Idle wait was interrupted"
2024-08-24T07:58:18.238Z	core/event            	INFO	""	1	"src/imap/idle.rs:86: INBOX.Sent: Idle wait was interrupted"
2024-08-24T07:58:18.240Z	core/event            	INFO	""	4	"src/smtp.rs:531: Selected rows from SMTP queue: [2, 3]."
2024-08-24T07:58:18.242Z	core/event            	INFO	""	1	"src/smtp.rs:531: Selected rows from SMTP queue: [2488, 2489, 2490, 2491, 2492, 2493, 2494]."
2024-08-24T07:58:18.245Z	core/event            	INFO	""	4	"src/net/dns.rs:64: Resolved snoot.red:465 into 194.181.228.45:465."
2024-08-24T07:58:18.246Z	core/event            	INFO	""	1	"src/net/dns.rs:64: Resolved snoot.red:465 into 194.181.228.45:465."
2024-08-24T07:58:18.263Z	core/event            	INFO	""	1	"src/imap.rs:709: 0 mails read from \"INBOX\"."
2024-08-24T07:58:18.264Z	core/event            	INFO	""	4	"src/imap.rs:709: 0 mails read from \"INBOX.DeltaChat\"."
2024-08-24T07:58:18.264Z	core/event            	INFO	""	4	"src/imap.rs:709: 0 mails read from \"INBOX.Sent\"."
2024-08-24T07:58:18.265Z	core/event            	INFO	""	1	"src/imap.rs:709: 0 mails read from \"INBOX.DeltaChat\"."
2024-08-24T07:58:18.265Z	core/event            	INFO	""	1	"src/imap.rs:709: 0 mails read from \"INBOX.Sent\"."
2024-08-24T07:58:18.265Z	core/event            	INFO	""	4	"src/imap.rs:709: 0 mails read from \"INBOX\"."
2024-08-24T07:58:18.265Z	core/event            	INFO	""	4	"src/imap/scan_folders.rs:31: Starting full folder scan"
2024-08-24T07:58:18.283Z	core/event            	INFO	""	4	"src/scheduler.rs:669: IMAP session supports IDLE, using it."
2024-08-24T07:58:18.284Z	core/event            	INFO	""	4	"src/scheduler.rs:669: IMAP session supports IDLE, using it."
2024-08-24T07:58:18.289Z	core/event            	INFO	""	1	"src/imap/scan_folders.rs:31: Starting full folder scan"
2024-08-24T07:58:18.301Z	core/event            	INFO	""	4	"src/imap/idle.rs:65: INBOX.Sent: Idle entering wait-on-remote state"
2024-08-24T07:58:18.301Z	core/event            	INFO	""	4	"src/imap/idle.rs:65: INBOX.DeltaChat: Idle entering wait-on-remote state"
2024-08-24T07:58:18.302Z	core/event            	INFO	""	4	"src/imap.rs:507: No new emails in folder \"INBOX.Archive\"."
2024-08-24T07:58:18.302Z	core/event            	INFO	""	1	"src/scheduler.rs:669: IMAP session supports IDLE, using it."
2024-08-24T07:58:18.303Z	core/event            	INFO	""	1	"src/scheduler.rs:669: IMAP session supports IDLE, using it."
2024-08-24T07:58:18.327Z	core/event            	INFO	""	1	"src/imap/idle.rs:65: INBOX.DeltaChat: Idle entering wait-on-remote state"
2024-08-24T07:58:18.328Z	core/event            	INFO	""	1	"src/imap/idle.rs:65: INBOX.Sent: Idle entering wait-on-remote state"
2024-08-24T07:58:18.328Z	core/event            	INFO	""	4	"src/imap.rs:507: No new emails in folder \"INBOX.Newsletter\"."
2024-08-24T07:58:18.328Z	core/event            	WARNING	""	4	"src/smtp/connect.rs:84: Failed to connect to 194.181.228.45:465: Unexpected greeting: \"220-wn09.webd.pl ESMTP Exim 4.96.2 #2 Sat, 24 Aug 2024 09:58:17 +0200 \\r\\n\".."
2024-08-24T07:58:18.328Z	core/event            	WARNING	""	4	"src/scheduler.rs:765: send_smtp_messages failed: Failed to send message: SMTP connection failure: Unexpected greeting: \"220-wn09.webd.pl ESMTP Exim 4.96.2 #2 Sat, 24 Aug 2024 09:58:17 +0200 \\r\\n\".."
2024-08-24T07:58:18.328Z	core/event            	INFO	""	4	"src/scheduler.rs:782: SMTP fake idle started."
2024-08-24T07:58:18.329Z	core/event            	INFO	""	4	"src/scheduler.rs:794: SMTP has messages to retry, planning to retry 1316 seconds later."
2024-08-24T07:58:18.329Z	core/event            	WARNING	""	1	"src/smtp/connect.rs:84: Failed to connect to 194.181.228.45:465: Unexpected greeting: \"220-wn09.webd.pl ESMTP Exim 4.96.2 #2 Sat, 24 Aug 2024 09:58:17 +0200 \\r\\n\".."
2024-08-24T07:58:18.329Z	core/event            	WARNING	""	1	"src/scheduler.rs:765: send_smtp_messages failed: Failed to send message: SMTP connection failure: Unexpected greeting: \"220-wn09.webd.pl ESMTP Exim 4.96.2 #2 Sat, 24 Aug 2024 09:58:17 +0200 \\r\\n\".."
2024-08-24T07:58:18.329Z	core/event            	INFO	""	1	"src/scheduler.rs:782: SMTP fake idle started."
2024-08-24T07:58:18.329Z	core/event            	INFO	""	1	"src/scheduler.rs:794: SMTP has messages to retry, planning to retry 1111 seconds later."

• Tried solutions: Tried another account connected to the same domain causing the same error. Thunderbird on the device sends messages succesfully and the Android and iOS app work normally too. Also tried reverting the flatpak versions to the previous release as it worked before, the issue still persisted.

[iequidoo]

This was apparently broken by d9c0e47, now lines starting with "220- " are skipped:

async fn skip_smtp_greeting<R: tokio::io::AsyncBufReadExt + Unpin>(stream: &mut R) -> Result<()> {
    let mut line = String::with_capacity(512);
    loop {
        let read = stream.read_line(&mut line).await?;
        if read == 0 {
            bail!("Unexpected EOF while reading SMTP greeting.");
        }
        if line.starts_with("220- ") {
            continue;

I think it should be "220-", i.e. w/o whitespace.

[link2xt]

Greeting is defined here: https://www.rfc-editor.org/rfc/rfc5321#page-47

[link2xt]

@iequidoo Could you branch it off tag v1.142.8? The fix should be released as v1.142.9.

[link2xt]

@iequidoo I have created branch stable, let's commit fixes there. Then merge tagged releases back into main.

[iequidoo]

Fixed by #5912 in stable. Will be merged to main after tagging v1.142.9