ssl connection strangely stops working

Dear List

I am not a very experienced user of jdbc although have been using
postgresql for many years having done many server installation and
administering them.

From three different systems (mac, windows, and centos virtualbox)
behind 1 ip address I had succeeded in getting ssl connection to a
remote server via jdbc. (That after much struggle on centOS
glassfish; turns out i had to run
"asadmin set domain.resources.jdbc-connection-pool.connectionPool.property.JDBC30DataSource=true"
at glassfish account)

On mac and windows the connection is set up via netbeans/glassfish.
All were working very well for about two weeks up until yesterday
evening.

Today all three connections stop working for no apparent reason. I
had not touched any settings on the postgresql server.

In server log I only get this,

LOG: could not accept SSL connection: sslv3 alert certificate unknown

Yes I googled this problem and find pages seemingly not relevant to my
problem. I know I have ssl connection right because it was working
just 24 hours ago with no changes in server or client settings.

Even weirder I can still connect to this server using psql from centOS
virtualbox. See this
------------------
/usr/local/pg/bin/psql -U mail -h server.address -p 5433 mail
Password for user mail:
psql (9.0.2)
SSL connection (cipher: DHE-RSA-AES256-SHA, bits: 256)
Type "help" for help.

mail=>
-----------

Any suggestions? Do I suddenly need to enter server ssl cert into
keystore of glassfish server now? But I didn't need it before!

Some webpages mention using property
sslfactory=org.postgresql.ssl.NonValidatingFactory

That does not seem to help much.

Thanks

mr wu