Are you the owner of the forum?
If so I would have expected you to have received an email 10 days ago warning you that the forum was scheduled for deletion. I would also expect that you would have received an email today containing a link to a ZIP file containing an archive of your forum which can be used to restore your forum. These emails may have gone to your spam folder so do check there.
There is a further set of issues that only Nabble can address that apply more generally:
# You have users are forwarded to is part of the JMeter forum and not Nabble's own site
# That page appears to be being used as an experimental area and contains features
not found on normal Nabble forums
# The text on that screen is out of date. There is no longer a forum search facility at:
http://www.nabble.com/free-apps/page1.html only some 200 pages with forums listed in a random order to browse through.
Hopefully, you can find the ZIP you need and post a link to it here and Nabble can sort some of the more general issues I mention.
Volunteer Helper - but recommending that users move off the platform!
Once the admin for GregHelp now deleted.