When you go to SWAT page, it responds with

HTTP/1.0 401 Authorization Required
WWW-Authenticate: Basic realm="SWAT"
Connection: close
Content-Type: text/html

When you enter bad username/password, you get response:

HTTP/1.0 401 Bad Authorization
Connection: close
Content-Type: text/html

This response is violating RFC1945. According to RFC all 401 responses must
include WWW-Authenticate field (section 9.4).

This prevents users of browser links-2.1pre14 from logging into SWAT when they
enter bad password first time.