From the Texecom manual:
18 - UDL Lockout
This output type activates when an attempt is made to upload/download with incorrect site details more than three times and deactivates after 4 hours or after a valid User code is entered.
Link to the page on manualslib: Link
To reset the UDL lock need to reboot the alarm with power.
Unplug the outlet and battery and plug them back in.
Make sure Tethebox has the correct ULD passcode before activation alarm on the timeline side to avoid ULD lock.
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Quick Reference Guide on official site: Link