IE浏览器代理导致teacup安装异常报错

IE浏览器代理会导致Tcl/tk无法使用teacup安装扩展。取消代理后恢复正常。

错误提示如下：

C:\Users\Phoenix>teacup list teacup
0 entities found

Problems which occurred during the operation:
* http://teapot.activestate.com :
ERROR: Cache Access Denied ERROR Cache Access Denied While
trying to retrieve the URL:
http://teapot.activestate.com/entity/name/teacup/list The
following error was encountered: Cache Access Denied. Sorry, you
are not currently allowed to request:
http://teapot.activestate.com/entity/name/teacup/list from this
cache until you have authenticated yourself. You need to use
Netscape version 2.0 or greater, or Microsoft Internet Explorer
3.0, or an HTTP/1.1 compliant browser for this to work. Please
contact the cache administrator if you have difficulties
authenticating yourself or change your default password.
Generated Thu, 28 Apr 2016 10:41:56 GMT by LibProxy
(squid/2.5.STABLE13)