Hi Ashutosh,
Thank you for your reply, I finally resolve this issue by update the hostagent, restart SMD in managed system side and change the parameter you mentioned above in solman side. There are only three or four SMDs in my landscape, I think the default value for the parameters is large enough, so I didn't try to enlarge the value yesterday. It's really weird. Anyway, thank you very much.
Best Regards,
Pany Pan