[Evolution] Evolution EWS stopped suddenly

[portsample <portsample blepsias net>]

I've had EWS configured properly for the last few weeks since the switch
to Exchange 2010, then today it started endlessly updating the mailbox. 

I've run "EWS_DEBUG=2 evolution" with the following output looping ad
infinitum,
                
                > Authorization: Basic [myc\jrlewis:********]
                > 
                > <?xml version="1.0" encoding="UTF-8" standalone="no"?>
                > <SOAP-ENV:Envelope
                xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"; 
xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"; xmlns:xsd="http://www.w3.org/1999/XMLSchema"; 
xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance";><SOAP-ENV:Header><types:RequestServerVersion 
xmlns:types="http://schemas.microsoft.com/exchange/services/2006/types"; 
Version="Exchange2007_SP1"/></SOAP-ENV:Header><SOAP-ENV:Body 
xmlns:messages="http://schemas.microsoft.com/exchange/services/2006/messages";><messages:SyncFolderHierarchy 
xmlns="http://schemas.microsoft.com/exchange/services/2006/types";><messages:FolderShape><BaseShape>AllProperties</BaseShape></messages:FolderShape></messages:SyncFolderHierarchy></SOAP-ENV:Body></SOAP-ENV:Envelope>
                  
                < HTTP/1.1 401 Unauthorized
                < Soup-Debug-Timestamp: 1345228435
                < Soup-Debug: ESoapMessage 1 (0x64bb80)
                < Server: Microsoft-IIS/7.5
                < Set-Cookie:
                exchangecookie=1de4be63ca134e9190e0b418b34dd396;
                expires=Sat, 17-Aug-2013 18:33:28 GMT; path=/; HttpOnly
                < WWW-Authenticate: Negotiate
                < WWW-Authenticate: NTLM
                < WWW-Authenticate: Basic realm="webmail.mycompany.com"
                < X-Powered-By: ASP.NET
                < Date: Fri, 17 Aug 2012 10:23:27 GMT
                < Content-Length: 0
                  
                > POST /EWS/Exchange.asmx HTTP/1.1
                > Soup-Debug-Timestamp: 1345228435
                > Soup-Debug: SoupSessionAsync 1 (0x7fbf04006000),
                ESoapMessage 1 (0x64bb80), SoupSocket 1 (0x1488ef0),
                restarted
                > Host: webmail.mycompany.com
                > User-Agent: Evolution/3.2.3
                > Connection: Keep-Alive
                > Content-Type: text/xml
                > Content-Length: 792
                > Authorization: Basic [myc\jrlewis:********]
                
Any suggestions regarding what the problem might be?
Whats'up with the "< HTTP/1.1 401 Unauthorized"?
TIA for reviewing this.