Better error message.

frontend/src/components/webmail/ComposeEmailForm.vue

@@ -436,7 +436,6 @@ watch(
 if (!route.query.uid) {
   const args =
     route.query.mailbox === constants.DRAFTS_FOLDER ? [route.query.mailid] : []
-  console.log(args)
   api.createComposeSession(...args).then((resp) => {
     const query = { ...route.query, uid: resp.data.uid }
     attachmentCount.value = resp.data.attachments?.length || 0

modoboa/webmail/lib/imaputils.py

@@ -783,6 +783,8 @@ class IMAPconnector:
             bcmd = "BODY.PEEK" if readonly else "BODY"
             to_fetch = f"(BODYSTRUCTURE {bcmd}[HEADER.FIELDS ({what})])"
         data = self._cmd("FETCH", mailid, to_fetch)
+        if int(mailid) not in data:
+            raise ImapError(f"Message with UID {mailid} not found in {mbox} folder")
         return data[int(mailid)]