For a fax greater than 50 pages to be successfully received, the line quality along the entire connection must be clear for an extended period of time. We can not control the line quality past a certain point. This is not just for FaxBetter it is for any fax.
 

Therefore, we would strongly recommend splitting the document into smaller groups of 50 pages or less and send concurrently. To split the fax for free we recommend this site.