Hey,
Do you get any errors in your SuiteCRM error log, or the PHP error log?
If so, I would suggest starting here, and looking into these, if they seem related/relevant
If not, I’d initially suggest checking your CRM’s Security Groups & Roles, to ensure your user is not part of any Role that may restrict viewing of the Detailview for Accounts/Contacts
If that doesn’t help, perhaps it would be worth doing a quick repair and rebuild?
(ie: Admin->Repair->Quick Repair and Rebuild)
Have you made any customisations to Accounts or Contacts?
If so, this may help with resolving issues
If neither of the above resolve your issues, perhaps it is worth having a read through this thread, where a user had a similar issue with Custom Modules?:
I’m not sure if the situation would be 100% comparable, but it might point you in the right direction