diff --git a/Cargo.lock b/Cargo.lock
index bb1cb961a..a88f51a09 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3283,6 +3283,7 @@ dependencies = [
  "governor",
  "indoc",
  "ipnetwork",
+ "lettre",
  "mas-iana",
  "mas-jose",
  "mas-keystore",
diff --git a/crates/cli/src/util.rs b/crates/cli/src/util.rs
index dee93caeb..a4ab8eba6 100644
--- a/crates/cli/src/util.rs
+++ b/crates/cli/src/util.rs
@@ -53,19 +53,25 @@ pub fn mailer_from_config(
     config: &EmailConfig,
     templates: &Templates,
 ) -> Result<Mailer, anyhow::Error> {
-    let from = config.from.parse()?;
-    let reply_to = config.reply_to.parse()?;
+    let from = config
+        .from
+        .parse()
+        .context("invalid email configuration: invalid 'from' address")?;
+    let reply_to = config
+        .reply_to
+        .parse()
+        .context("invalid email configuration: invalid 'reply_to' address")?;
     let transport = match config.transport() {
         EmailTransportKind::Blackhole => MailTransport::blackhole(),
         EmailTransportKind::Smtp => {
             // This should have been set ahead of time
             let hostname = config
                 .hostname()
-                .context("invalid configuration: missing hostname")?;
+                .context("invalid email configuration: missing hostname")?;
 
             let mode = config
                 .mode()
-                .context("invalid configuration: missing mode")?;
+                .context("invalid email configuration: missing mode")?;
 
             let credentials = match (config.username(), config.password()) {
                 (Some(username), Some(password)) => Some(mas_email::SmtpCredentials::new(
@@ -74,7 +80,7 @@ pub fn mailer_from_config(
                 )),
                 (None, None) => None,
                 _ => {
-                    anyhow::bail!("invalid configuration: missing username or password");
+                    anyhow::bail!("invalid email configuration: missing username or password");
                 }
             };
 
diff --git a/crates/config/Cargo.toml b/crates/config/Cargo.toml
index e07215f3c..403e38c24 100644
--- a/crates/config/Cargo.toml
+++ b/crates/config/Cargo.toml
@@ -22,6 +22,7 @@ camino = { workspace = true, features = ["serde1"] }
 chrono.workspace = true
 figment.workspace = true
 ipnetwork = { version = "0.20.0", features = ["serde", "schemars"] }
+lettre.workspace = true
 schemars.workspace = true
 ulid.workspace = true
 url.workspace = true
diff --git a/crates/config/src/sections/email.rs b/crates/config/src/sections/email.rs
index 24fdabd5c..23668de3c 100644
--- a/crates/config/src/sections/email.rs
+++ b/crates/config/src/sections/email.rs
@@ -6,8 +6,9 @@
 
 #![allow(deprecated)]
 
-use std::num::NonZeroU16;
+use std::{num::NonZeroU16, str::FromStr};
 
+use lettre::message::Mailbox;
 use schemars::JsonSchema;
 use serde::{de::Error, Deserialize, Serialize};
 
@@ -199,6 +200,14 @@ impl ConfigurationSection for EmailConfig {
             EmailTransportKind::Blackhole => {}
 
             EmailTransportKind::Smtp => {
+                if let Err(e) = Mailbox::from_str(&self.from) {
+                    return Err(error_on_field(figment::error::Error::custom(e), "from"));
+                }
+
+                if let Err(e) = Mailbox::from_str(&self.reply_to) {
+                    return Err(error_on_field(figment::error::Error::custom(e), "reply_to"));
+                }
+
                 match (self.username.is_some(), self.password.is_some()) {
                     (true, true) | (false, false) => {}
                     (true, false) => {
@@ -237,6 +246,14 @@ impl ConfigurationSection for EmailConfig {
             EmailTransportKind::Sendmail => {
                 let expected_fields = &["from", "reply_to", "transport", "command"];
 
+                if let Err(e) = Mailbox::from_str(&self.from) {
+                    return Err(error_on_field(figment::error::Error::custom(e), "from"));
+                }
+
+                if let Err(e) = Mailbox::from_str(&self.reply_to) {
+                    return Err(error_on_field(figment::error::Error::custom(e), "reply_to"));
+                }
+
                 if self.command.is_none() {
                     return Err(missing_field("command"));
                 }