"Not sufficient" to file charges still does not mean NO EVIDENCE, no matter how many times you post it. There was no documentary evidence to support the charges. Conspiracy is difficult to prove without documentary evidence to back it up, or eyewitness testimony.
Both Manafort and Stone refused to cooperate or correct the lies they told to the FBI or Congress. If either of them had testified honestly to the FBI or Congress, would the evidence have existed to charge Trump? We 'll never know. Because Donald Trump dangled pardons to both men if they refused to "rat him out". You can't "rat someone out" unless you have the goods on the them.