iis 7.5 - iis7.5 many-to-one client certificate mapping causes error status 500 -

iis 7.5 - iis7.5 many-to-one client certificate mapping causes error status 500 -

we trying implement client certificate authentication in iis 7.5. have configured many-to-one mapping, disabled other authentication modes , cert-authentication seems work correctly: can correctly read certificate info test .aspx page , authenticated username 1 configured in many-to-one mappings.

however, though seems work correctly, each "new" browser session causes 1 "extra" error status 500 row in iis log, before authentication successful:

#fields: date time s-ip cs-method cs-uri-stem cs-uri-query s-port ... cs-host sc-status sc-substatus sc-win32-status time-taken 2013-02-12 09:46:35 10.40.64.45 /certtest.aspx - 443 - ... - site.mydomain.com 500 0 64 31 2013-02-12 09:46:35 10.40.64.45 /certtest.aspx - 443 - ... - site.mydomain.com 200 0 0 734

same "extra" error status 500 issue happens file, e.g. images, .css, .js, it's not problem in certtest.aspx file.

any ideas, cause error status 500 in iis?

it seems managed solve issue setting sslalwaysnegoclientcert metabase property true.

technet article iis6.0 (!) admin reference

iis-7.5 client-certificates