Problem routing to action from actionlink

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C#7.0

Hello, I am using a @Html.Actionlink(..) callo to redirect my page to a specific action in a controller .
My call is the following :

@Html.ActionLink(P.Cert,  "RedirectToRate","Panels", new { @sede = P.Sed1 + P.Sed2, @catg = P.Catg, @cert = P.Cert,  @anno = P.AnnoValidita }, new { @style = "background-color : white ;width :70% " })

I can see that it's rendered as :

<a href="/Panels/RedirectToRate?sede=0100&catg=885&cert=01030580" style="background-color : white ;width :70% ">01030580</a>

which is what I want.
in the "Panels" controller I have the "RedirectToRate" action whose contract is as follows :

ActionResult RedirectToRate(string sede="", string catg="", string cert="", string anno="")

my route maps are the following

routes.MapRoute(
               name: "Default",
               url: "{controller}/{action}/{id}",
               defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
           );

         routes.MapRoute(
               name: "Access",
               url: "{controller}/{action}/{pensione}/{sede}/{catg}/{cert}/{anno}",
               defaults: new { controller = "Home", action = "Index",  sede = UrlParameter.Optional, catg = UrlParameter.Optional, cert = UrlParameter.Optional, anno = UrlParameter.Optional }
           );

When I click the link, I have a runtime error, I don't know how and where, so that i am not able to catch it .... any idea why ?
thanks

What I have tried:

changing route mapping

reversing Controller/Action order in the actionlink call