This just had this happen on a Windows 2003 server with a client’s client.
Any .asmx page would return a 404 error like this IIS log line shows:
2009-11-06 09:46:05 127.0.0.1 GET /MyVirtualDirectory/MyWebService.asmx – 80 – 127.0.0.1 Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.2;+SV1;+.NET+CLR+1.1.4322;+.NET+CLR+2.0.50727;+.NET+CLR+3.0.4506.2152;+.NET+CLR+3.5.30729) 404 2 1260
Searching for “iis 404 2 1260 asp.net” found this top from Marc Valk, that solved the issue: ASP.NET v2.0.5727 was prohibited to run.
Which means that none of the ASP.NET bound extensions would work: they all returned 404 errors.
(Note: if you are wondering where your IIS log files are, this post shows you).
–jeroen
