how to resolve this error
nano@nano-Satellite-C50-A:~$ sudo flexran.start
[sudo] password for nano:
EXEC: -p 2210 -n 9999
/snap/flexran/5/run: 40: /snap/flexran/5/run: snap: Permission denied
Is this a snap you created?
If it is, then you need to make sure that your build process sets executable permission on the run file.