diff --git a/Telegram/SourceFiles/core/local_url_handlers.cpp b/Telegram/SourceFiles/core/local_url_handlers.cpp
index 0740d8d15..b4bfe00a4 100644
--- a/Telegram/SourceFiles/core/local_url_handlers.cpp
+++ b/Telegram/SourceFiles/core/local_url_handlers.cpp
@@ -172,7 +172,7 @@ bool ResolveUsername(const Match &match, const QVariant &context) {
 	const auto domain = params.value(qsl("domain"));
 	const auto valid = [](const QString &domain) {
 		return qthelp::regex_match(
-			qsl("^[a-z0-9\\.\\_]+$"),
+			qsl("^[a-zA-Z0-9\\.\\_]+$"),
 			domain,
 			{}
 		).valid();