HART 40v self propelled mower not propelling

[GroundLoop]

Worked fine when it was put away last season. Blade spins but will not move forward. Has anyone seen this before?

 

[1 Lucky Texan]

Worked fine when it was put away last season. Blade spins but will not move forward. Has anyone seen this before?

maybe someone with experience will reply but, I did find this on YouTube,