Below are some troubleshooting tips:
(1) This may be happening if you added by mistake a prefix or area code or 1 or 2 digits to the BLACKLIST. To fix this, you will need to remove this (these) number(s) from the BLACKLIST. To do so, please press the BLACKLIST button and the use the scroll buttons to browse the list of phone numbers you have added to the BLACKLIST. If you find a single digit or 2 digit number there, press the REMOVE button to delete from the BLACKLIST.
(2) If problem continues, clear all the numbers in the BLACKLIST by pressing BLACKLIST, and then holding the REMOVE button for more than 3 seconds. You will be prompted to enter the PASSword, which is 0000 (default). NOTE: You will need to have a handset connected on the PHONE port of the call blocker in order to enter the password.
(3) Another possible solution may consist on you having your call blocker installed in parallel using a 2-way splitter. Please refer to the manual for more details.
(4) Another possible reason why this is happening is due to interference. Please make sure your call blocker is at least 2 feet away from any other telecom equipment (phones, modems, etc).
If problem continues, please contact our technical support team. You may need to send it in for repair or replacement under the warranty.