diff --git a/lib/tunnelbroker/peer-to-peer-context.js b/lib/tunnelbroker/peer-to-peer-context.js
--- a/lib/tunnelbroker/peer-to-peer-context.js
+++ b/lib/tunnelbroker/peer-to-peer-context.js
@@ -146,7 +146,7 @@
             };
             await sendMessageToPeer(encryptedMessage);
           } catch (e) {
-            if (!e.message?.includes(olmSessionErrors.sessionDoesNotExists)) {
+            if (!e.message?.includes(olmSessionErrors.sessionDoesNotExist)) {
               console.log(`Error sending messages to peer ${peerDeviceID}`, e);
               break;
             }
@@ -325,7 +325,7 @@
             payload: JSON.stringify(encryptedMessage),
           });
         } catch (e) {
-          if (!e.message?.includes(olmSessionErrors.sessionDoesNotExists)) {
+          if (!e.message?.includes(olmSessionErrors.sessionDoesNotExist)) {
             console.log(
               `Error sending messages to peer ${recipient.deviceID}`,
               e,
diff --git a/lib/utils/olm-utils.js b/lib/utils/olm-utils.js
--- a/lib/utils/olm-utils.js
+++ b/lib/utils/olm-utils.js
@@ -129,7 +129,7 @@
   // This definition should remain in sync with the value defined in
   // the corresponding .cpp file
   // at `native/cpp/CommonCpp/CryptoTools/CryptoModule.cpp`.
-  sessionDoesNotExists: 'SESSION_DOES_NOT_EXISTS',
+  sessionDoesNotExist: 'SESSION_DOES_NOT_EXIST',
   // Error thrown when attempting to decrypt a message encrypted
   // with an already replaced old session.
   // This definition should remain in sync with the value defined in
diff --git a/native/cpp/CommonCpp/CryptoTools/CryptoModule.cpp b/native/cpp/CommonCpp/CryptoTools/CryptoModule.cpp
--- a/native/cpp/CommonCpp/CryptoTools/CryptoModule.cpp
+++ b/native/cpp/CommonCpp/CryptoTools/CryptoModule.cpp
@@ -14,7 +14,7 @@
 
 // This definition should remain in sync with the value defined in
 // the corresponding JavaScript file at `lib/utils/olm-utils.js`.
-const std::string SESSION_DOES_NOT_EXISTS_ERROR{"SESSION_DOES_NOT_EXISTS"};
+const std::string SESSION_DOES_NOT_EXIST_ERROR{"SESSION_DOES_NOT_EXIST"};
 const std::string INVALID_SESSION_VERSION_ERROR{"INVALID_SESSION_VERSION"};
 
 CryptoModule::CryptoModule(std::string id) : id{id} {
@@ -386,7 +386,7 @@
     const std::string &targetDeviceId,
     const std::string &content) {
   if (!this->hasSessionFor(targetDeviceId)) {
-    throw std::runtime_error{SESSION_DOES_NOT_EXISTS_ERROR};
+    throw std::runtime_error{SESSION_DOES_NOT_EXIST_ERROR};
   }
   return this->sessions.at(targetDeviceId)->encrypt(content);
 }
@@ -395,7 +395,7 @@
     const std::string &targetDeviceId,
     EncryptedData &encryptedData) {
   if (!this->hasSessionFor(targetDeviceId)) {
-    throw std::runtime_error{SESSION_DOES_NOT_EXISTS_ERROR};
+    throw std::runtime_error{SESSION_DOES_NOT_EXIST_ERROR};
   }
   auto session = this->sessions.at(targetDeviceId);
   if (encryptedData.sessionVersion.has_value() &&
diff --git a/web/shared-worker/worker/worker-crypto.js b/web/shared-worker/worker/worker-crypto.js
--- a/web/shared-worker/worker/worker-crypto.js
+++ b/web/shared-worker/worker/worker-crypto.js
@@ -555,7 +555,7 @@
     }
     const olmSession = cryptoStore.contentSessions[deviceID];
     if (!olmSession) {
-      throw new Error(olmSessionErrors.sessionDoesNotExists);
+      throw new Error(olmSessionErrors.sessionDoesNotExist);
     }
     const encryptedContent = olmSession.session.encrypt(content);
 
@@ -577,7 +577,7 @@
     }
     const olmSession = cryptoStore.contentSessions[deviceID];
     if (!olmSession) {
-      throw new Error(olmSessionErrors.sessionDoesNotExists);
+      throw new Error(olmSessionErrors.sessionDoesNotExist);
     }
 
     const encryptedContent = olmSession.session.encrypt(content);
@@ -632,7 +632,7 @@
 
     const olmSession = cryptoStore.contentSessions[deviceID];
     if (!olmSession) {
-      throw new Error(olmSessionErrors.sessionDoesNotExists);
+      throw new Error(olmSessionErrors.sessionDoesNotExist);
     }
 
     if (
@@ -663,7 +663,7 @@
 
     const olmSession = cryptoStore.contentSessions[deviceID];
     if (!olmSession) {
-      throw new Error(olmSessionErrors.sessionDoesNotExists);
+      throw new Error(olmSessionErrors.sessionDoesNotExist);
     }
 
     if (