First of all it's a great plugin...My website was fuctioning normally...not at all bulky.
But it conflicts with wordpress default commenting system...at times I see a default comment and at other page I could find jetpack comments...To resolve this I erroneously deactivated the entire plugin which made a fiasco in the comment system.
Whereever default commenting system was viewable before...it has no change but where jetpack comments was seen...there I find a message 'blog token not found'.
Did reinstall the jetpack plugin but the same problem persists.
Please find my site.