diff --git a/app/src/main/java/jp/juggler/subwaytooter/api/entity/Acct.kt b/app/src/main/java/jp/juggler/subwaytooter/api/entity/Acct.kt
index c9040735..775a83e1 100644
--- a/app/src/main/java/jp/juggler/subwaytooter/api/entity/Acct.kt
+++ b/app/src/main/java/jp/juggler/subwaytooter/api/entity/Acct.kt
@@ -45,7 +45,11 @@ class Host private constructor(
             val cached = hostSet[srcArg]
             if (cached != null) return cached
             val src = srcArg.removeUrlSchema()
-            val ascii = IDN.toASCII(src, IDN.ALLOW_UNASSIGNED).lowercase()
+            val ascii = if( """[^A-Za-z0-9._-]""".toRegex().find(src)!=null){
+                IDN.toASCII(src, IDN.ALLOW_UNASSIGNED).lowercase()
+            }else{
+                IDN.toASCII(src, IDN.ALLOW_UNASSIGNED).lowercase()
+            }
             val pretty = IDN.toUnicode(src, IDN.ALLOW_UNASSIGNED)
             val host = if (ascii == pretty) Host(ascii) else Host(ascii, pretty)
             hostSet[src] = host
diff --git a/app/src/main/java/jp/juggler/subwaytooter/dialog/LoginForm.kt b/app/src/main/java/jp/juggler/subwaytooter/dialog/LoginForm.kt
index 9edbd74d..b4d984fd 100644
--- a/app/src/main/java/jp/juggler/subwaytooter/dialog/LoginForm.kt
+++ b/app/src/main/java/jp/juggler/subwaytooter/dialog/LoginForm.kt
@@ -40,7 +40,7 @@ class LoginForm(
         private val log = LogCategory("LoginForm")
 
         @Suppress("RegExpSimplifiable")
-        val reBadLetter = """[^A-Za-z0-9:;._-]+""".toRegex()
+        val reBadChars = """([^\p{L}\p{N}A-Za-z0-9:;._-]+)""".toRegex()
 
         fun AppCompatActivity.showLoginForm(
             onClickOk: (
@@ -192,8 +192,7 @@ class LoginForm(
             return null
         }
 
-        //
-        reBadLetter.findAll(s).joinToString("") { it.value }.notEmpty()?.let {
+        reBadChars.findAll(s).joinToString("") { it.value }.notEmpty()?.let {
             showError(activity.getString(R.string.server_host_name_cant_contains_it, it))
             return null
         }