Can't connect to server: invalid name or server not reachable

Details:

  • we’ve been successfully running Spark IM for years - very few issues
  • this morning users began receiving this message when connecting
  • I rebooted the server (several times now) - installed MS updates too
  • After each reboot, some users could logon - about one-third total
  • Tried reinstalling same version “openfire_3_6_4.exe”
  • Spark client version - 2.6.3
  • I can ping the server
  • I cannot logon to the admin console
  • I tried using the IP address in the server box
  • I tried using “Use OLS SSL port method” - no go
  • Some users are on Terminal Servers, remaining on standalone workstations - no ryhme or reason - no consistencey for the problem
  • No errors in Event Log, but erros in the Open File log folder - need help understanding error log

Thoughts to fix? Thanks! Big Fish