DNS Records error

Hi all,

I'm connecting my domain to Squarespace - it was originally parked via 123-reg. I've been able to update the DNS records aside for 1 'A' record:  198.49.23.144. When I input it, I get the error message "Record data is invalid." 

I've been able to add the other 3 'A' records with no problem but for some reason it won't accept this one. Can someone tell me what I'm doing wrong please?

Ada