Github is the preferable place:
- Search Opened issues. Maybe somebody has already reported the same issue.
- Also search already Closed issues. There might be similar issue with a solution from the past.
- Follow the Troubleshooting guide.
- If still no luck or you have some suggestion/question/feature request open a New ticket
You can also use the inbuilt product-support of the blendermarket.
The engine used to recognize the phonemes and convert them to the 9 mouth cue types is Daniel Wolf's Rhubarb Lip Sync application. The add-on ships this CLI ( command line interface) application as part of the installation zip file in the bin folder.
The rhubarb lipsync NG is a complete rework of the original rhubarb lipsync addon based on the same principles and ideas.
The NG in the name stands for Next generation. This is to distinguish this reworked addon from the original one.