diff --git a/src/EmailProcessor.ts b/src/EmailProcessor.ts
index e191c16..19da74c 100644
--- a/src/EmailProcessor.ts
+++ b/src/EmailProcessor.ts
@@ -33,9 +33,9 @@ export class EmailProcessor {
 
         const targets: IEmailTarget[] = [];
 
-        for (const email of (message.to || [])) targets.push({address: email.address, name: email.name, source: 'to'});
-        for (const email of (message.cc || [])) targets.push({address: email.address, name: email.name, source: 'cc'});
-        for (const email of (message.bcc || [])) targets.push({address: email.address, name: email.name, source: 'bcc'});
+        for (const email of (message.to || [])) targets.push({ address: email.address.toLowerCase(), name: email.name, source: 'to' });
+        for (const email of (message.cc || [])) targets.push({ address: email.address.toLowerCase(), name: email.name, source: 'cc' });
+        for (const email of (message.bcc || [])) targets.push({ address: email.address.toLowerCase(), name: email.name, source: 'bcc' });
 
         const primaryFrom = message.from[0];