The 'Ghost' Boost

Normally, after a convention ends...you get a 'boost'.  Maybe three points....maybe even five points. 

So today, the poll folks came out and said that the Democratic Convention ended, and what Joe Biden got in terms of a boost....was zero....more or less.

Blame?  No one discusses this part of the strategy, or if the Convention was seriously flawed.  You can't even say that Joe Biden is at fault.

Normally, there would be a message, which the Convention would lay out, and people would feel enthusiasm.  So that simply isn't there. 

A problem in November?