Auto reversal Success, Auto post failed?

Hi All,

We have setup the auto reversal criteria set(Next period first day).Auto Reversal and Auto post are checked

as a process auto reverse runs when a new period is opened, when we checked for a particular transaction it is erred when auto posts.

Situation:

1. Original entry successfully auto reversed when a new period was opened

2. auto reversal entry for Auto posting failed.

What reasons could be when original entry successfully auto reversed and Auto posting was failed.

Thanks,

Vinay