Cannot add hosts to RHV -M (webui)

Hi,

My lab setup is as follows:

1 x dns server
1 x RHV-M (running on RHEL 7.3 VM)
1 x RHV-H (bare metal thin host)

in administration portal of RHV-M, I dont see complete options. for example it doesnt let me chose default data center (neither is it listed) in the drop down menu of add new hosts UI. I dont see "OK" buttons on UI for various options. webUI is extremely slow in response. is it possible to remove and reinstall WebUI part of RHV-M. or how can I troubleshoot further.

not new to virtualization but new to Red Hat Virtualization. further planning to use RHV-H as part of openstack deployment in future.

thanks