vesta ssl not working on 0.9.8 r26

[qiaofeng]

Hello,
vesta ssl is not woking with Lets Encrypt Support on production server. vestacp version is 0.9.28 and never updated to 1.0.0. it's actually a severe problem.

config changes could be saved without problems but SSL Support status always be no. don't have any clue to figure it out.

any help would be appreciated.
and we'd like to pay the service help for fixing this severe problem

thanks