diff --git a/src/ejabberd_acme.erl b/src/ejabberd_acme.erl
index 44d93da2c..74579f549 100644
--- a/src/ejabberd_acme.erl
+++ b/src/ejabberd_acme.erl
@@ -1220,9 +1220,7 @@ opt_type(acme) ->
     fun(L) ->
 	    lists:map(
 	      fun({ca_url, URL}) ->
-		      URL1 = binary_to_list(URL),
-		      {ok, _} = http_uri:parse(URL1),
-		      {ca_url, URL1};
+		      {ca_url, misc:try_url(URL)};
 		 ({contact, Contact}) ->
 		      [<<_, _/binary>>, <<_, _/binary>>] =
 			  binary:split(Contact, <<":">>),
diff --git a/src/misc.erl b/src/misc.erl
index 9f72ebf88..7aaebffc9 100644
--- a/src/misc.erl
+++ b/src/misc.erl
@@ -35,7 +35,7 @@
 	 now_to_usec/1, usec_to_now/1, encode_pid/1, decode_pid/2,
 	 compile_exprs/2, join_atoms/2, try_read_file/1, get_descr/2,
 	 css_dir/0, img_dir/0, js_dir/0, msgs_dir/0, sql_dir/0,
-	 read_css/1, read_img/1, read_js/1]).
+	 read_css/1, read_img/1, read_js/1, try_url/1]).
 
 %% Deprecated functions
 -export([decode_base64/1, encode_base64/1]).
@@ -219,6 +219,25 @@ try_read_file(Path) ->
 	    erlang:error(badarg)
     end.
 
+%% @doc Checks if the URL is valid HTTP(S) URL and converts its name to binary.
+%%      Fails with `badarg` otherwise. The function is intended for usage
+%%      in configuration validators only.
+-spec try_url(binary() | string()) -> binary().
+try_url(URL) ->
+    case http_uri:parse(URL) of
+	{ok, {Scheme, _, _, _, _, _}} when Scheme /= http, Scheme /= https ->
+	    ?ERROR_MSG("Unsupported URI scheme: ~s", [URL]),
+	    erlang:error(badarg);
+	{ok, {_, _, Host, _, _, _}} when Host == ""; Host == <<"">> ->
+	    ?ERROR_MSG("Invalid URL: ~s", [URL]),
+	    erlang:error(badarg);
+	{ok, _} ->
+	    iolist_to_binary(URL);
+	{error, _} ->
+	    ?ERROR_MSG("Invalid URL: ~s", [URL]),
+	    erlang:error(badarg)
+    end.
+
 -spec css_dir() -> file:filename().
 css_dir() ->
     get_dir("css").
diff --git a/src/mod_http_upload.erl b/src/mod_http_upload.erl
index 43a1999e1..65251e056 100644
--- a/src/mod_http_upload.erl
+++ b/src/mod_http_upload.erl
@@ -178,18 +178,14 @@ mod_opt_type(dir_mode) ->
 mod_opt_type(docroot) ->
     fun iolist_to_binary/1;
 mod_opt_type(put_url) ->
-    fun(<<"http://", _/binary>> = URL) -> URL;
-       (<<"https://", _/binary>> = URL) -> URL
-    end;
+    fun misc:try_url/1;
 mod_opt_type(get_url) ->
-    fun(<<"http://", _/binary>> = URL) -> URL;
-       (<<"https://", _/binary>> = URL) -> URL;
-       (undefined) -> undefined
+    fun(undefined) -> undefined;
+       (URL) -> misc:try_url(URL)
     end;
 mod_opt_type(service_url) ->
-    fun(<<"http://", _/binary>> = URL) -> URL;
-       (<<"https://", _/binary>> = URL) -> URL;
-       (undefined) -> undefined
+    fun(undefined) -> undefined;
+       (URL) -> misc:try_url(URL)
     end;
 mod_opt_type(custom_headers) ->
     fun(Headers) ->
diff --git a/src/mod_register.erl b/src/mod_register.erl
index 3737ff96b..ea822e339 100644
--- a/src/mod_register.erl
+++ b/src/mod_register.erl
@@ -616,7 +616,9 @@ mod_opt_type({welcome_message, subject}) ->
 mod_opt_type({welcome_message, body}) ->
     fun iolist_to_binary/1;
 mod_opt_type(redirect_url) ->
-    fun iolist_to_binary/1.
+    fun(<<>>) -> <<>>;
+       (URL) -> misc:try_url(URL)
+    end.
 
 mod_options(_Host) ->
     [{access, all},