Unable to log into user calendar

[msmukesh5]

I tried adding a user, making it super user, able to fetch user information.
But when try logging with that user account with login link i get an error and bedework ask me to try again.

Secondly i am getting some exceptions in the background
edu.rpi.cct.webdav.servlet.shared.WebdavException: edu.rpi.cct.webdav.servlet.shared.WebdavException: edu.rpi.cct.webdav.servlet.shared.WebdavException: java.lang.NullPointerException

Caused by: edu.rpi.cct.webdav.servlet.shared.WebdavException: edu.rpi.cct.webdav.servlet.shared.WebdavException: java.lang.NullPointerException

wasn't able to figure it out.
NEED HELP !!