Stuck at grep command when using otp script

[ttasc]

OS: Arch
Script: otp
I get this error and completely stuck in dmenu:

grep: Invalid range end

I know the script is stuck on this line:

echo "$name" | grep -q -- "^[A-z0-9-]\+$" && break

I don't know what's wrong with my system. If it's not a problem with the script itself, please give me some suggestions to avoid this error. Thanks a lot everyone.