diff --git a/src/erlcloud_aws.erl b/src/erlcloud_aws.erl
index 840639e11..92e28d22a 100644
--- a/src/erlcloud_aws.erl
+++ b/src/erlcloud_aws.erl
@@ -17,7 +17,7 @@ aws_request(Method, Host, Path, Params, AccessKeyID, SecretAccessKey) ->
 
     QueryToSign = erlcloud_http:make_query_string(QParams),
     RequestToSign = [string:to_upper(atom_to_list(Method)), $\n,
-                     Host, $\n, Path, $\n, QueryToSign],
+                     string:to_lower(Host), $\n, Path, $\n, QueryToSign],
     Signature = base64:encode(crypto:sha_mac(SecretAccessKey, RequestToSign)),
     
     Query = [QueryToSign, "&Signature=", erlcloud_http:url_encode(Signature)],
diff --git a/src/erlcloud_http.erl b/src/erlcloud_http.erl
index dad407efc..0a83944f0 100644
--- a/src/erlcloud_http.erl
+++ b/src/erlcloud_http.erl
@@ -20,8 +20,7 @@ url_encode([Char|String], Accum)
        Char >= $a, Char =< $z;
        Char >= $0, Char =< $9;
        Char =:= $-; Char =:= $_;
-       Char =:= $.; Char =:= $~;
-       Char =:= $: ->
+       Char =:= $.; Char =:= $~ ->
     url_encode(String, [Char|Accum]);
 url_encode([Char|String], Accum)
   when Char >=0, Char =< 255 ->