Accessing SIPR (https://uolr3.leeds.ac.uk/sipr) normally requires a user name and password. The user name is normally your personnel number and a password you will have set when you first logged in.
In some versions of Chrome you may be prompted for additional login details:
If you see a pop up window such as that shown above, please enter your IT user name without @leeds.ac.uk and your normal SAP GUI password. You should only have to do this once.
A workaround would be to use an alternative browser such as Microsoft Edge.