diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4163df0..54e7f71 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -33,6 +33,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
current streak has already been notified. When the account recovers the flag is
cleared and a single recovery notification is sent; the next failure streak will
then fire a fresh alert.
+## v0.10.2 (2026-05-03)
+
+### Bug Fixes
+
+- Add sender_email to UserSmtpConfig to fix SMTP From header (501 bad sender address)
+ ([`a21e2f7`](https://github.com/christianlouis/InboxConverge/commit/a21e2f7df62ef79271efab172a88d1ead06bfe67))
+
## v0.10.1 (2026-05-03)
@@ -44,6 +51,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
## v0.10.0 (2026-05-03)
+### Bug Fixes
+
+- **SMTP Fallback sender address**: Add `sender_email` field to `UserSmtpConfig` so the SMTP `From:` header uses a real email address instead of the SMTP authentication token. Providers like Postmark use a UUID API token as the username, which caused a `501 Bad sender address syntax` error. The new field is optional; when left blank the `username` value is used as a fallback (preserving existing behaviour for providers where username == email address). Includes a new Alembic migration (`0003`) and a Sender Email input in the Settings page.
+
## v0.9.2 (2026-05-03)
diff --git a/backend/alembic/versions/0003_add_smtp_sender_email.py b/backend/alembic/versions/0003_add_smtp_sender_email.py
new file mode 100644
index 0000000..384c168
--- /dev/null
+++ b/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")
diff --git a/backend/app/api/v1/endpoints/users.py b/backend/app/api/v1/endpoints/users.py
index 98ccaf8..142838e 100644
--- a/backend/app/api/v1/endpoints/users.py
+++ b/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()
diff --git a/backend/app/models/database_models.py b/backend/app/models/database_models.py
index 016e431..01f2ad2 100644
--- a/backend/app/models/database_models.py
+++ b/backend/app/models/database_models.py
@@ -484,6 +484,7 @@ 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),
diff --git a/backend/app/models/schemas.py b/backend/app/models/schemas.py
index cb772f0..109c551 100644
--- a/backend/app/models/schemas.py
+++ b/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
diff --git a/backend/app/services/mail_processor.py b/backend/app/services/mail_processor.py
index 14acb85..778a11b 100644
--- a/backend/app/services/mail_processor.py
+++ b/backend/app/services/mail_processor.py
@@ -1444,7 +1444,9 @@ 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()
diff --git a/backend/app/workers/tasks.py b/backend/app/workers/tasks.py
index 6192970..ecdd2ae 100644
--- a/backend/app/workers/tasks.py
+++ b/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,
}
diff --git a/frontend/src/app/settings/page.tsx b/frontend/src/app/settings/page.tsx
index db9c4a5..b775472 100644
--- a/frontend/src/app/settings/page.tsx
+++ b/frontend/src/app/settings/page.tsx
@@ -148,6 +148,7 @@ function SettingsContent() {
host: 'smtp.gmail.com',
port: 587,
username: '',
+ sender_email: '',
password: '',
use_tls: true,
});
@@ -187,6 +188,7 @@ function SettingsContent() {
host: smtpConfig.host,
port: smtpConfig.port,
username: smtpConfig.username,
+ sender_email: smtpConfig.sender_email,
use_tls: smtpConfig.use_tls,
password: '', // never pre-fill password
}));
@@ -246,7 +248,7 @@ function SettingsContent() {
mutationFn: smtpApi.remove,
onSuccess: () => {
queryClient.invalidateQueries({ queryKey: ['smtp-config'] });
- setSmtpForm({ host: 'smtp.gmail.com', port: 587, username: '', password: '', use_tls: true });
+ setSmtpForm({ host: 'smtp.gmail.com', port: 587, username: '', sender_email: '', password: '', use_tls: true });
},
});
@@ -302,6 +304,7 @@ function SettingsContent() {
host: smtpForm.host,
port: smtpForm.port,
username: smtpForm.username,
+ sender_email: smtpForm.sender_email,
password: smtpForm.password || undefined,
use_tls: smtpForm.use_tls,
});
@@ -601,6 +604,21 @@ function SettingsContent() {
/>
+
+
+
+
+ The From: address used when forwarding mail. Required when your SMTP username is an API token rather than an email address (e.g. Postmark, SendGrid).
+