cannot see Central repo

I added central repo (Secured) in CMC. Gave full permissions. and also added users in DS management console to access the central repo.

Login to designer and trying to add central repo. Cannot see the central repo in the list.

Is there any limit on how many central repos can be added?

I have 3 central repos already in the system. I can see all of them, except the newly added central repo.

DS 4.2 SP4

Repo: Oracle

Windows 2008