diff --git a/README.md b/README.md
index 0351a30..f78e15b 100644
--- a/README.md
+++ b/README.md
@@ -11,13 +11,14 @@ _*Note, that this project is not associated with the [Bitwarden](https://bitward
   - [Updating the bitwarden image](#updating-the-bitwarden-image)
 - [Configuring bitwarden service](#configuring-bitwarden-service)
   - [Disable registration of new users](#disable-registration-of-new-users)
+  - [Enabling HTTPS](#enabling-https)
+  - [Enabling U2F authentication](#enabling-u2f-authentication)
   - [Changing persistent data location](#changing-persistent-data-location)
     - [/data prefix:](#data-prefix)
     - [database name and location](#database-name-and-location)
     - [attachments location](#attachments-location)
     - [icons cache](#icons-cache)
   - [Changing the API request size limit](#changing-the-api-request-size-limit)
-  - [Enabling HTTPS](#enabling-https)
   - [Other configuration](#other-configuration)
 - [Building your own image](#building-your-own-image)
 - [Building binary](#building-binary)
@@ -41,6 +42,14 @@ Basically full implementation of Bitwarden API is provided including:
  * Vault API support 
  * Serving the static files for Vault interface
  * Website icons API
+ * Authenticator and U2F support
+ 
+## Missing features
+* Email confirmation
+* Other two-factor systems:
+  * YubiKey OTP (if your key supports U2F, you can use that)
+  * Duo
+  * Email codes
 
 ## Docker image usage
 
@@ -109,6 +118,44 @@ docker run -d --name bitwarden \
   mprasil/bitwarden:latest
 ```
 
+### Enabling HTTPS
+To enable HTTPS, you need to configure the `ROCKET_TLS`.
+
+The values to the option must follow the format:
+```
+ROCKET_TLS={certs="/path/to/certs.pem",key="/path/to/key.pem"}
+```
+Where:
+- certs: a path to a certificate chain in PEM format
+- key: a path to a private key file in PEM format for the certificate in certs
+
+```sh
+docker run -d --name bitwarden \
+  -e ROCKET_TLS={certs='"/ssl/certs.pem",key="/ssl/key.pem"}' \
+  -v /ssl/keys/:/ssl/ \
+  -v /bw-data/:/data/ \
+  -v /icon_cache/ \
+  -p 443:443 \
+  mprasil/bitwarden:latest
+```
+Note that you need to mount ssl files and you need to forward appropriate port.
+
+### Enabling U2F authentication
+To enable U2F authentication, you must be serving bitwarden_rs from an HTTPS domain with a valid certificate (Either using the included
+HTTPS options or with a reverse proxy). We recommend using a free certificate from Let's Encrypt.
+
+After that, you need to set the `DOMAIN` environment variable to the same address from where bitwarden_rs is being served:
+
+```sh
+docker run -d --name bitwarden \
+  -e DOMAIN=https://bw.domain.tld \
+  -v /bw-data/:/data/ \
+  -p 80:80 \
+  mprasil/bitwarden:latest
+```
+
+Note that the value has to include the `https://` and it may include a port at the end (in the format of `https://bw.domain.tld:port`) when not using `443`.
+
 ### Changing persistent data location
 
 #### /data prefix:
@@ -184,28 +231,6 @@ docker run -d --name bitwarden \
   mprasil/bitwarden:latest
 ```
 
-### Enabling HTTPS
-To enable HTTPS, you need to configure the `ROCKET_TLS`.
-
-The values to the option must follow the format:
-```
-ROCKET_TLS={certs="/path/to/certs.pem",key="/path/to/key.pem"}
-```
-Where:
-- certs: a path to a certificate chain in PEM format
-- key: a path to a private key file in PEM format for the certificate in certs
-
-```sh
-docker run -d --name bitwarden \
-  -e ROCKET_TLS={certs='"/ssl/certs.pem",key="/ssl/key.pem"}' \
-  -v /ssl/keys/:/ssl/ \
-  -v /bw-data/:/data/ \
-  -v /icon_cache/ \
-  -p 443:443 \
-  mprasil/bitwarden:latest
-```
-Note that you need to mount ssl files and you need to forward appropriate port.
-
 ### Other configuration
 
 Though this is unlikely to be required in small deployment, you can fine-tune some other settings like number of workers using environment variables that are processed by [Rocket](https://rocket.rs), please see details in [documentation](https://rocket.rs/guide/configuration/#environment-variables).
diff --git a/src/api/core/two_factor.rs b/src/api/core/two_factor.rs
index 031711f..420362a 100644
--- a/src/api/core/two_factor.rs
+++ b/src/api/core/two_factor.rs
@@ -217,6 +217,10 @@ lazy_static! {
 
 #[post("/two-factor/get-u2f", data = "<data>")]
 fn generate_u2f(data: JsonUpcase<PasswordData>, headers: Headers, conn: DbConn) -> JsonResult {
+    if !CONFIG.domain_set {
+        err!("`DOMAIN` environment variable is not set. U2F disabled")
+    }
+
     let data: PasswordData = data.into_inner().data;
 
     if !headers.user.check_valid_password(&data.MasterPasswordHash) {
@@ -299,8 +303,6 @@ fn activate_u2f(data: JsonUpcase<EnableU2FData>, headers: Headers, conn: DbConn)
             .delete(&conn)
             .expect("Error deleting U2F register challenge");
 
-        println!("RegisterResponse {:#?}", &data.DeviceResponse);
-
         let response_copy: RegisterResponseCopy =
             serde_json::from_str(&data.DeviceResponse).expect("Can't parse RegisterResponse data");
 
@@ -388,7 +390,6 @@ impl Into<Registration> for RegistrationCopy {
 }
 
 fn _parse_registrations(registations: &str) -> Vec<Registration> {
-    println!("Registrations {:#?}", registations);
     let registrations_copy: Vec<RegistrationCopy> =
         serde_json::from_str(registations).expect("Can't parse RegistrationCopy data");
 
@@ -418,8 +419,6 @@ pub fn validate_u2f_login(user_uuid: &str, response: &str, conn: &DbConn) -> Api
 
     let challenge = match tf_challenge {
         Some(tf_challenge) => {
-            println!("challenge {:#?}", &tf_challenge.data);
-
             let challenge: Challenge = serde_json::from_str(&tf_challenge.data)
                 .expect("Can't parse U2fLoginChallenge data");
             tf_challenge
@@ -437,8 +436,6 @@ pub fn validate_u2f_login(user_uuid: &str, response: &str, conn: &DbConn) -> Api
 
     let registrations = _parse_registrations(&twofactor.data);
 
-    println!("response {:#?}", response);
-
     let response: SignResponse =
         serde_json::from_str(response).expect("Can't parse SignResponse data");
 
diff --git a/src/api/identity.rs b/src/api/identity.rs
index b14c198..fb6120e 100644
--- a/src/api/identity.rs
+++ b/src/api/identity.rs
@@ -14,6 +14,8 @@ use util::{self, JsonMap};
 
 use api::{ApiResult, JsonResult};
 
+use CONFIG;
+
 pub fn routes() -> Vec<Route> {
     routes![login]
 }
@@ -216,7 +218,7 @@ fn _json_err_twofactor(providers: &[i32], user_uuid: &str, conn: &DbConn) -> Api
         match TwoFactorType::from_i32(*provider) {
             Some(TwoFactorType::Authenticator) => { /* Nothing to do for TOTP */ }
 
-            Some(TwoFactorType::U2f) => {
+            Some(TwoFactorType::U2f) if CONFIG.domain_set => {
                 let request = two_factor::generate_u2f_login(user_uuid, conn)?;
                 let mut challenge_list = Vec::new();
 
diff --git a/src/util.rs b/src/util.rs
index 78d169a..4a18680 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -3,7 +3,8 @@
 ///
 #[macro_export]
 macro_rules! err {
-    ($err:expr, $err_desc:expr, $msg:expr) => {
+    ($err:expr, $err_desc:expr, $msg:expr) => {{
+        println!("ERROR: {}", $msg);
         err_json!(json!({
           "error": $err,
           "error_description": $err_desc,
@@ -13,14 +14,13 @@ macro_rules! err {
             "Object": "error"
           }
         }))
-    };
+    }};
     ($msg:expr) => { err!("default_error", "default_error_description", $msg) }
 }
 
 #[macro_export]
 macro_rules! err_json {
     ($expr:expr) => {{
-        println!("ERROR: {}", $expr);
         return Err($crate::rocket::response::status::BadRequest(Some($crate::rocket_contrib::Json($expr))));
     }}
 }