In certain situations, Spark displays “Incorrect username or password” although the supplied credentials appear correct. I believe the problem may be related to certain characters in the password. I have tested that the following passwords are problematic:
<foobar (starts with less-than symbol)
&foobar (starts with ampersand)
foobar (starts with space)
These passwords work when using other XMPP clients. The server I am testing against is running Jive Messenger 2.3.0, and it is connected to an external LDAP server for authentication.