Hydraulic brake stopped working

[Evansterry5]

Hi guys my bike has been in the shed for awhile and the hydraulic brake worked when i last used it but now the rear brake has just stopped working please help.

 

[Levo-Lon]

What is the issue..
solid lever? Soft lever?

 

[fossyant]

Please explain how it has stopped working. Is the lever pulling to the bars, are the pads moving ? How proficient a mechanic are you ?