Hi Dennis,
First I suggest you check the authorizations for both roles
========
/SAPSRM/BIDDER
/SAPSRM/BIDDER_EHP1
========
Maybe somebody has modified them ever.
Then please run report pol_d01 for application id SAPSRM_B_RFXANDAUCTIONS and the portal user,
and delete the resulted entries.
After this, please retry again.
Best regards,
Ivy