That happens if the number is from a country different than th one the phone is set up for. The cellphone system ignores the +, it ignores whether or not the country code is there if it's the country you're in and, if some apps have trouble with they, the developer wasn't following the rules. Spaces in phone numbers aren't real - they're displayed for you, but there's no <space> character in the phone number itself. (<Space> in text is an actual character just like a or -, but there's no <space> character in phone numbers - it's a different coding system.)