PC, the first thing I would check is the Automation License Manager. Run a license check to see if the license is showing valid. It looks like the license for the Audit Trail feature is what the problem is, according to the message text you shared. This is why the audit trail is not working. The HMI thinks it is not properly licensed.
Check to see how many licenses you have installed and how many are in use. I have had issues with licenses in the past where for whatever reason they show up as bad. In that case, I have had to call the Siemens support number with my System ID and have them send a reset code.
To check a license, select it in the License Manager, and select Check from the License menu item at the top of the window. The popup will indicate the number of licenses installed and how many are in use.
The TP900, I am guessing, is either connected via Profibus or Profinet. It needs to be added to and configured in the TIA Portal hardware configuration, typically in the same project as the CPU. There are some configuration items that can be accessed via the front panel of the HMI at power on. I would consult the manual for these items.