Hey there Omesiri thanks for reaching out, could you post a link to your workspace so that we can take a look at what is happening? Also just out of curiosity is the table that you are trying to use as an exclusion list a CSV table, as in the table was created by uploading a CSV into Clay.
If so the exclusion feature currently cannot read tables that were created from a CSV, it can only take in tables that were generated from within Clay via one of the search option.