Unable to run the simple_switch_grpc in the system even after proper installation!

*** Starting L2 nodes
s1 …

s1 log (from /tmp/bmv2-s1-log):simple_switch_grpc --device-id 1 -i 1@s1-eth1 -i 2@s1-eth2 -i 3@s1-eth3 --thrift-port 50001 --log-console -Linfo …/p4src/build/no_controller.json – --cpu-port 255 --grpc-server-addr 0.0.0.0:39855--------------------------------------------------------------------------------simple_switch_grpc: Permission deniedTraceback (most recent call last):
File “mn_code.py”, line 181, in
topology()
File “mn_code.py”, line 72, in topology
net.start()
File “/usr/local/lib/python3.8/dist-packages/mininet_wifi-2.6-py3.8.egg/mn_wifi/net.py”, line 822, in start
nodeL2.start(self.controllers)
File “/usr/local/lib/python3.8/dist-packages/mininet_wifi-2.6-py3.8.egg/mn_wifi/bmv2.py”, line 361, in start
self.waitBmv2Start()
File “/usr/local/lib/python3.8/dist-packages/mininet_wifi-2.6-py3.8.egg/mn_wifi/bmv2.py”, line 531, in waitBmv2Start
raise Exception(“Switch did not start before timeout”)

on the fourth line of the error you have a “Permission denied” message.
So perhaps you need to run the switch with root privilege.
try re-running the switch using sudo.