You are getting below error message when opening the Web Gui/Fiori/NWBC or any URLs from the SAP system.
Solution
The resolution is taken/shared as in SAP Wiki,
Open transaction code SECSTORE and look for entry /HMAC_INDEP/CL_HTTP_SERVER_NET and/or /HMAC_CLIENT/CL_HTTP_SERVER_NET.
Delete the entry if it’s marked as red.
You can now re-open the SAP Web Gui / Fiori / NWBC or any other SAP URLs
