Priors point to code errrors in the ROM. As a last hurrah be sure to unplug all memory cards and reset+wipe one last time. If it fails, head to XDA Forums and try another ROM.
I defer to XDA for roms, how to install, etc.
I recently updated my Galaxy tab 3 as i haven't been on it in a good year or two. After the update installed, it now keeps coming up with this message, "Unfortunately, KeyguardTestActivity has stopped". I have wipe data/factory reset three times now and this message keeps popping up continuously. Please help me!!