diff --git a/app/Http/Requests/SaveClientPortalSettings.php b/app/Http/Requests/SaveClientPortalSettings.php
index cd81bf7d31dd..00a239c590b7 100644
--- a/app/Http/Requests/SaveClientPortalSettings.php
+++ b/app/Http/Requests/SaveClientPortalSettings.php
@@ -44,7 +44,7 @@ class SaveClientPortalSettings extends Request
         if (Utils::isNinja()) {
             if ($this->custom_link == 'subdomain') {
                 $subdomain = substr(strtolower($input['subdomain']), 0, MAX_SUBDOMAIN_LENGTH);
-                $input['subdomain'] = preg_replace('/[^a-zA-Z0-9_\-\.]/', '', $subdomain);
+                $input['subdomain'] = preg_replace('/[^a-zA-Z0-9\-\.]/', '', $subdomain);
                 $input['iframe_url'] = null;
             } else {
                 $iframeURL = substr(strtolower($input['iframe_url']), 0, MAX_IFRAME_URL_LENGTH);
diff --git a/app/Models/Account.php b/app/Models/Account.php
index 61643b68df36..118dedc22880 100644
--- a/app/Models/Account.php
+++ b/app/Models/Account.php
@@ -1711,6 +1711,13 @@ Account::creating(function ($account)
     LookupAccount::createAccount($account->account_key, $account->company_id);
 });
 
+Account::updating(function ($account) {
+    $dirty = $account->getDirty();
+    if (array_key_exists('subdomain', $dirty)) {
+        LookupAccount::updateAccount($account->account_key, $account);
+    }
+});
+
 Account::updated(function ($account) {
     // prevent firing event if the invoice/quote counter was changed
     // TODO: remove once counters are moved to separate table
diff --git a/app/Models/LookupAccount.php b/app/Models/LookupAccount.php
index 605769de00c6..65c45360786c 100644
--- a/app/Models/LookupAccount.php
+++ b/app/Models/LookupAccount.php
@@ -55,6 +55,24 @@ class LookupAccount extends LookupModel
         return $this->lookupCompany->dbServer->name;
     }
 
+    public static function updateAccount($accountKey, $account)
+    {
+        if (! env('MULTI_DB_ENABLED')) {
+            return;
+        }
+
+        $current = config('database.default');
+        config(['database.default' => DB_NINJA_LOOKUP]);
+
+        $lookupAccount = LookupAccount::whereAccountKey($accountKey)
+                            ->firstOrFail();
+
+        $lookupAccount->subdomain = $account->subdomain;
+        $lookupAccount->save();
+
+        config(['database.default' => $current]);
+    }
+
     public static function validateField($field, $value, $account = false)
     {
         if (! env('MULTI_DB_ENABLED')) {
@@ -62,7 +80,7 @@ class LookupAccount extends LookupModel
         }
 
         $current = config('database.default');
-        
+
         config(['database.default' => DB_NINJA_LOOKUP]);
 
         $lookupAccount = LookupAccount::where($field, '=', $value)->first();
diff --git a/resources/views/accounts/client_portal.blade.php b/resources/views/accounts/client_portal.blade.php
index 26a1e5d86803..ce767f19a826 100644
--- a/resources/views/accounts/client_portal.blade.php
+++ b/resources/views/accounts/client_portal.blade.php
@@ -467,7 +467,7 @@ iframe.src = '{{ rtrim(SITE_URL ,'/') }}/view/'
         var input = $('#subdomain');
         var val = input.val();
         if (!val) return;
-        val = val.replace(/[^a-zA-Z0-9_\-]/g, '').toLowerCase().substring(0, {{ MAX_SUBDOMAIN_LENGTH }});
+        val = val.replace(/[^a-zA-Z0-9\-]/g, '').toLowerCase().substring(0, {{ MAX_SUBDOMAIN_LENGTH }});
         input.val(val);
     }