diff --git a/lib/httpx/plugins/oauth.rb b/lib/httpx/plugins/oauth.rb
index a5a16f5d..2722a79d 100644
--- a/lib/httpx/plugins/oauth.rb
+++ b/lib/httpx/plugins/oauth.rb
@@ -60,16 +60,17 @@ module HTTPX
         end
 
         def load(http)
-          return unless @token_endpoint && @token_endpoint_auth_method && @grant_type && @scope
+          return if @token_endpoint && @token_endpoint_auth_method && @grant_type && @scope
 
-          metadata = http.get("#{issuer}/.well-known/oauth-authorization-server").raise_for_status.json
+          metadata = http.get("#{@issuer}/.well-known/oauth-authorization-server").raise_for_status.json
 
-          @token_endpoint = metadata["token_endpoint"]
-          @scope = metadata["scopes_supported"]
-          @grant_type = Array(metadata["grant_types_supported"]).find { |gr| SUPPORTED_GRANT_TYPES.include?(gr) }
-          @token_endpoint_auth_method = Array(metadata["token_endpoint_auth_methods_supported"]).find do |am|
+          @token_endpoint ||= metadata["token_endpoint"]
+          @scope ||= metadata["scopes_supported"]
+          @grant_type ||= Array(metadata["grant_types_supported"]).find { |gr| SUPPORTED_GRANT_TYPES.include?(gr) }
+          @token_endpoint_auth_method ||= Array(metadata["token_endpoint_auth_methods_supported"]).find do |am|
             SUPPORTED_AUTH_METHODS.include?(am)
           end
+          nil
         end
 
         def merge(other)