I got a HTTP 500 error in SAP EP when I tryed to launch Bex reports or tools, error message « Issuer of SSO ticket is not authorized ».
In my case it is because portal certificate is no longer valid in the ABAP stack.
Import again portal certificate in ABAP stack.
Start VisualAdmin, select Services > Key Storage. Select TicketKeystore in Views, select SAPLogonTicketKeypair-cert in Entries, then click on the Export button dans save the file. This is the public portal certificate that we will import in abap stack.
In transaction STRUSTSSO2, I choose to delete everything after having saved other relevant certificate (for example the one for BO)
Select System PSE, right click, create, then OK or save.
Then import again public portal certificate, add it to the certificate List, and add it to ACL using SID TBI and system number (client) 500. Save, check the all thing.
Then import again the BO certificate, add it to the certificate list and add it to ACL using SID TBI and client 000. Save.
Every thing should be ok.