fix: add sender_email to UserSmtpConfig to fix SMTP From header (501 bad sender address)

Agent-Logs-Url: https://github.com/christianlouis/InboxConverge/sessions/dc853384-976a-46e5-945b-60c9a9cce638

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

backend/alembic/versions/0003_add_smtp_sender_email.py

@@ -0,0 +1,36 @@
+"""Add sender_email column to user_smtp_configs
+
+Revision ID: 0003
+Revises: 0002
+Create Date: 2026-05-03
+
+Adds a ``sender_email`` column to ``user_smtp_configs``.
+
+SMTP providers such as Postmark use an API token (UUID) as the SMTP username
+for authentication, but require a real email address as the ``From:`` header.
+This column stores the address that should appear as the sender; when blank,
+the existing ``username`` value is used as a fallback so existing rows remain
+fully functional.
+
+Using IF NOT EXISTS makes the migration idempotent against fresh installs
+where create_all() already created the column.
+"""
+
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = "0003"
+down_revision = "0002"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.execute(
+        "ALTER TABLE user_smtp_configs "
+        "ADD COLUMN IF NOT EXISTS sender_email VARCHAR(255) NOT NULL DEFAULT ''"
+    )
+
+
+def downgrade() -> None:
+    op.execute("ALTER TABLE user_smtp_configs DROP COLUMN IF EXISTS sender_email")

backend/app/api/v1/endpoints/users.py

@@ -72,6 +72,7 @@ async def get_smtp_config(
         host=config.host,  # type: ignore[arg-type]
         port=config.port,  # type: ignore[arg-type]
         username=config.username,  # type: ignore[arg-type]
+        sender_email=config.sender_email,  # type: ignore[arg-type]
         use_tls=config.use_tls,  # type: ignore[arg-type]
         has_password=bool(config.encrypted_password),
         created_at=config.created_at,  # type: ignore[arg-type]
@@ -95,6 +96,7 @@ async def upsert_smtp_config(
         config.host = config_in.host  # type: ignore[assignment]
         config.port = config_in.port  # type: ignore[assignment]
         config.username = config_in.username  # type: ignore[assignment]
+        config.sender_email = config_in.sender_email  # type: ignore[assignment]
         config.use_tls = config_in.use_tls  # type: ignore[assignment]
         if config_in.password is not None:
             config.encrypted_password = encrypt_credential(config_in.password)  # type: ignore[assignment]
@@ -104,6 +106,7 @@ async def upsert_smtp_config(
             host=config_in.host,
             port=config_in.port,
             username=config_in.username,
+            sender_email=config_in.sender_email,
             encrypted_password=(
                 encrypt_credential(config_in.password) if config_in.password else ""
             ),
@@ -120,6 +123,7 @@ async def upsert_smtp_config(
         host=config.host,  # type: ignore[arg-type]
         port=config.port,  # type: ignore[arg-type]
         username=config.username,  # type: ignore[arg-type]
+        sender_email=config.sender_email,  # type: ignore[arg-type]
         use_tls=config.use_tls,  # type: ignore[arg-type]
         has_password=bool(config.encrypted_password),
         created_at=config.created_at,  # type: ignore[arg-type]
@@ -174,7 +178,7 @@ async def test_smtp_config(
             "plain",
             "utf-8",
         )
-        msg["From"] = config.username  # type: ignore[index]
+        msg["From"] = config.sender_email or config.username  # type: ignore[index]
         msg["To"] = recipient
         msg["Date"] = formatdate(localtime=True)
         msg["Message-ID"] = make_msgid()

backend/app/models/database_models.py

@@ -475,6 +475,7 @@ class UserSmtpConfig(Base):
     username = Column(String(255), nullable=False, default="")
     encrypted_password = Column(Text, nullable=False, default="")
     use_tls = Column(Boolean, default=True)
+    sender_email = Column(String(255), nullable=False, default="")
 
     created_at = Column(
         DateTime(timezone=True),

backend/app/models/schemas.py

@@ -481,6 +481,7 @@ class UserSmtpConfigBase(BaseModel):
     host: str = "smtp.gmail.com"
     port: int = Field(587, gt=0, lt=65536)
     username: str = ""
+    sender_email: str = ""
     use_tls: bool = True
 
 

backend/app/services/mail_processor.py

@@ -1256,7 +1256,9 @@ class MailProcessor:
 
                 # Create forwarding message
                 forward_msg = MIMEMultipart("mixed")
-                forward_msg["From"] = smtp_config["username"]
+                forward_msg["From"] = (
+                    smtp_config.get("sender_email") or smtp_config["username"]
+                )
                 forward_msg["To"] = destination
                 forward_msg["Date"] = formatdate(localtime=True)
                 forward_msg["Message-ID"] = make_msgid()

backend/app/workers/tasks.py

@@ -210,6 +210,7 @@ async def process_mail_account(account_id: int):
                         "host": user_smtp.host,
                         "port": user_smtp.port,
                         "username": user_smtp.username,
+                        "sender_email": user_smtp.sender_email or "",
                         "password": decrypt_credential(user_smtp.encrypted_password),  # type: ignore[arg-type]
                         "use_tls": user_smtp.use_tls,
                     }