authenticate error

source tree 1 6 24 0 unable to clone repository due to authentication error.
web browser login to bitbucket.org goes successfully, but login from source tree fails with following error message in windows event log

• <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
• <System>
  <Provider Name="Application" />
  <EventID Qualifiers="0">0</EventID>
  <Level>3</Level>
  <Task>0</Task>
  <Keywords>0x80000000000000</Keywords>
  <TimeCreated SystemTime="2015-12-01T18:25:37.000000000Z" />
  <EventRecordID>17327</EventRecordID>
  <Channel>Application</Channel>
  <Computer>cpl_note</Computer>
  <Security />
  </System>
• <EventData>
  <Data>slf4net: The factory resolver AppConfigFactoryResolver returned null from GetFactory(). The fallback no operation logger factory will be used instead. Application information: Application domain: Askpass.exe Application path: C:\Program Files (x86)\Atlassian\SourceTree\ Machine name: CPL_NOTE</Data>
  </EventData>
  </Event>