Getting authentication failure when logging into kibana

I am trying to log into kibana as the elastic user to do some maintenance but the login fails -- server shows: Authentication of [elastic] was terminated by realm [reserved] - failed to authenticate user [elastic]

I can use same credentials via curl fine:

rful011@secmonprd01:~$ curl -ks --noproxy \* -u elastic  -XGET https://secmonprd01.its.auckland.ac.nz:9200/_cluster/health?pretty
Enter host password for user 'elastic':
{
  "cluster_name" : "test",
  "status" : "green",

I tried restarting kibana but that did not make any difference.

Any idea what is going on?

Hmmmm.... It now works fine -- so far as I can tell nothing has changed.