diff --git a/client/src/components/ui/Guide/MobileConfigForm.js b/client/src/components/ui/Guide/MobileConfigForm.js
index ce9a6942..f726b40c 100644
--- a/client/src/components/ui/Guide/MobileConfigForm.js
+++ b/client/src/components/ui/Guide/MobileConfigForm.js
@@ -14,7 +14,7 @@ import {
     toNumber,
 } from '../../../helpers/form';
 import {
-    validateClientId,
+    validateConfigClientId,
     validateServerName,
     validatePort,
     validateIsSafePort,
@@ -132,7 +132,7 @@ const MobileConfigForm = ({ invalid }) => {
                         component={renderInputField}
                         className="form-control"
                         placeholder={i18next.t('client_id_placeholder')}
-                        validate={validateClientId}
+                        validate={validateConfigClientId}
                     />
                 </div>
                 <div className="form__group form__group--settings">
diff --git a/client/src/helpers/constants.js b/client/src/helpers/constants.js
index f9431cf6..195efdb3 100644
--- a/client/src/helpers/constants.js
+++ b/client/src/helpers/constants.js
@@ -24,7 +24,7 @@ export const R_UNIX_ABSOLUTE_PATH = /^(\/[^/\x00]+)+$/;
 // eslint-disable-next-line no-control-regex
 export const R_WIN_ABSOLUTE_PATH = /^([a-zA-Z]:)?(\\|\/)(?:[^\\/:*?"<>|\x00]+\\)*[^\\/:*?"<>|\x00]*$/;
 
-export const R_CLIENT_ID = /^[a-z0-9-]{1,64}$/;
+export const R_CLIENT_ID = /^[a-z0-9-]{1,63}$/;
 
 export const HTML_PAGES = {
     INSTALL: '/install.html',
diff --git a/client/src/helpers/validators.js b/client/src/helpers/validators.js
index 25a7168d..7075ca47 100644
--- a/client/src/helpers/validators.js
+++ b/client/src/helpers/validators.js
@@ -83,6 +83,21 @@ export const validateClientId = (value) => {
     return undefined;
 };
 
+/**
+ * @param value {string}
+ * @returns {undefined|string}
+ */
+export const validateConfigClientId = (value) => {
+    if (!value) {
+        return undefined;
+    }
+    const formattedValue = value.trim();
+    if (formattedValue && !R_CLIENT_ID.test(formattedValue)) {
+        return 'form_error_client_id_format';
+    }
+    return undefined;
+};
+
 /**
  * @param value {string}
  * @returns {undefined|string}