SRDF Script is getting failed...?

In my environment SRDF script will run for every 3 hrs.SRDF was configured to 8D and 9D directors.8D director got dead as shown below.But replication was not happening automatically with 9D director .Manually i  have to run SRDF commands to complete the replication.

I want to know why the replication is not happening with 9D director automatically.?

symcfg -sid **** list -ra all

Symmetrix ID: ********

                 S Y M M E T R I X    R D F    D I R E C T O R S

                                         Remote        Local    Remote

Ident  Symb  Num  Slot  Type       Attr  SymmID        RA Grp   RA Grp  Status

RF-8D   08D   56     8  RDF-BI-DIR   -   -              2 (01)   -      Dead

                                     -   -              3 (02)   -

                                     -   -              5 (04)   -

                                     -   -              8 (07)   -

                                     -   -             10 (09)   -

                                     -   -             11 (0A)   -

                                     -   -             15 (0E)   -

                                     -   -             16 (0F)   -

RF-9D   09D   57     9  RDF-R1       -   ********       8 (07)   8 (07) Online

                                     -   ********      10 (09)  10 (09)

                                     -   ********      11 (0A)  11 (0A)

                                     -   ********      15 (0E)  15 (0E)

                                     -   ********      2 (01)   2 (01)

                                     -   ********      3 (02)   3 (02)

                                     -   ********      5 (04)   5 (04)

                                     -   ********      16 (0F)  16 (0F)

Thanks in Advance.