error when fuzzing

~/HDL/symbiflow-arch-defs/third_party/prjxray/fuzzers/011-clb-ffconfig$ make run
make clean
make[1]: Entering directory '/home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/fuzzers/011-clb-ffconfig'
rm -rf build run.ok
make[1]: Leaving directory '/home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/fuzzers/011-clb-ffconfig'
make database
make[1]: Entering directory '/home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/fuzzers/011-clb-ffconfig'
mkdir -p build
if [ -f /home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/fuzzers/011-clb-ffconfig/generate.sh ]; then \
    export "CLBN=0"; \
    bash /home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/fuzzers/011-clb-ffconfig/generate.sh build/specimen_001; \
else \
    bash /home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/utils/top_generate.sh build/specimen_001; \
fi
+ source /home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/utils/top_generate.sh
++ set -ex
++ export FUZDIR=/home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/fuzzers/011-clb-ffconfig
++ FUZDIR=/home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/fuzzers/011-clb-ffconfig
++ source /home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/utils/genheader.sh
+++ '[' -z artix7 ']'
+++ set -ex
+++ export FUZDIR=/home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/fuzzers/011-clb-ffconfig
+++ FUZDIR=/home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/fuzzers/011-clb-ffconfig
+++ test 1 -ge 1
+++ test '!' -e ''
+++ export SPECDIR=build/specimen_001
+++ SPECDIR=build/specimen_001
+++ mkdir -p build/specimen_001
+++ cd build/specimen_001
++++ echo build/specimen_001
++++ md5sum
++++ cut -c1-8
+++ export SEED=ddcf076c
+++ SEED=ddcf076c
++++ sed 's/specimen_0*//'
+++++ pwd
++++ basename /home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/fuzzers/011-clb-ffconfig/build/specimen_001
+++ export SEEDN=1
+++ SEEDN=1
+++ echo build/specimen_001
+++ md5sum
+++ cut -c1-8
++ echo '`define SEED 32'\''hddcf076c'
++ make -f /home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/utils/top_generate.mk
make[2]: Entering directory '/home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/fuzzers/011-clb-ffconfig/build/specimen_001'
if [ -f /home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/fuzzers/011-clb-ffconfig/top.py ] ; then python3 /home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/fuzzers/011-clb-ffconfig/top.py >top.v; fi
touch top.v.ok
/home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/utils/vivado.sh -mode batch -source /home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/fuzzers/011-clb-ffconfig/generate.tcl

****** Vivado v2017.2 (64-bit)
  **** SW Build 1909853 on Thu Jun 15 18:39:10 MDT 2017
  **** IP Build 1909766 on Thu Jun 15 19:58:00 MDT 2017
    ** Copyright 1986-2017 Xilinx, Inc. All Rights Reserved.

source /home/jack/HDL/symbiflow-arch-defs/third_party/prjxray/fuzzers/011-clb-ffconfig/generate.tcl
# create_project -force -part $::env(XRAY_PART) design design
ERROR: [Common 17-685] Unable to load Tcl app xilinx::xsim
ERROR: [Common 17-69] Command failed: ERROR: [Common 17-685] Unable to load Tcl app xilinx::xsim

INFO: [Common 17-206] Exiting Vivado at Thu Dec 17 11:43:12 2020...