[Constraints 18-4610] Tandem stage 1 cell 'refclk_ibuf' has the property HD.TANDEM_IP_PBLOCK set to 'Stage1_Main'. It also has a conflicting LOC constraint set to 'GTHE4_COMMON_X0Y4'. This site is outside of pblock 'pcie4_uscale_plus_0_i_inst_pcie4_uscale_plus_0_Stage1_main'. Please resolve this conflict by removing the LOC constraint or changing the value of HD.TANDEM_IP_PBLOCK to a pblock that contains the site.
You need to resize the pblock. 'GTHE4_COMMON_X0Y4' this site si outside the pblock. Please create an IP example design(you can refer the below video link) and put the correct constraint to resize the Pblock.