Below are some reasons that may cause the call blocker to block all incoming calls:
1) There is a prefix or area code in the BLACKLIST that may cause this. Please make sure you remove all numbers less than 3 digits from single the BLACKLIST.
2) The feature to block calls with no caller ID is ON. Please make sure you turn OFF this feature (SET 6) following step 6 in the manual.
3) If you still have this issue, try installing the call blocker in parallel using a 2-way splitter or another phone jack (if available).
4) If none of the above works, please contact us.