Hi @manojndsu,
This error is occurring because the file you are attempting to import is NOT a distance matrix, nor is it LSMatFormat. It is an "OTU Table". I have already recommended that you read the importing tutorial at qiime2.org to learn more about how to import various data types into QIIME 2. In your case, you will want to follow the instructions shown here to first convert your OTU table to biom-format before importing to QIIME 2: