hi, joe.

below code in  UrlRewriter.cs in line 323

//////////////////////////////////////////////////////////////////////////////////////////////////////////

              // get any additional params besides pageid
                string separator = string.Empty;
                foreach (string key in app.Request.QueryString.AllKeys)
                {
                    if (key != "pageid")
                    {
                        originalQueryString.Append( separator + key + "="
                            + app.Request.QueryString.Get(key)); // Should be HttpUtility.UrlEncode(app.Request.QueryString.Get(key), System.Text.Encoding.UTF8));
                        
                        if(separator.Length == 0)separator = "&";

                    }
                }

///////////////////////////////////////////////////////////////////////////////////////////////////////////

for example:

if don't use HttpUtility.UrlEncode:

below param:

notify_id=RqPnCoPT3K9%252Fvwbh3I739xaCNUyHkrikGC%252F3Q2PGJ9s0wcZGEDmsdFEC5W54lMid8VVq

after  UrlRewriter will become

notify_id=RqPnCoPT3K9%2fvwbh3I739xaCNUyHkrikGC%2f3Q2PGJ9s0wcZGEDmsdFEC5W54lMid8VVq

​lost "52"

​After use HttpUtility.UrlEncode then will ok.

If you can get rid of param pageid from app.Request.QueryString directly,  don't use foreach ... then HttpUtility.UrlEncode will be more better.

Thanks.