Check LIMS log for following error message:

Application Error while processing request: / 
System.Data.OracleClient requires Oracle client software version 8.1.7 or greater.

To resolve navigate to Oracle client installation on LIMS server for example:

C:\app\client\product\19.0.0 | Mouse click on install folder for example "client_1" and select properties | Mouse client on "Security" tab on top then add "Authenticated Users" group with Read & Execute, List Folder Contents, and Read permissions then mouse click on Apply and OK.