IP whitelist

Hello I got an IP with the following format:

80.XX.****.251/32

When I try to add it to the whitelist I receive the following error:

"Invalid CIDR"

Since it's a public IP from a company I can not change the IP protocol. How could I add it to the whitelist properly?

I'm not an expert on this matter, so I've be reading a lot of info. Does the /32 means it's a IPv4 address and hence if I add 80.XX.****.251 without the /32 will work?

Thanks you