Good day! Try to send sms from magento and SMS Nitfier.
1. To russian number 79817487722 sms sended from magento correct. I could see them in atrio logs. But dont recieve it to the phone.

2. With finnish number sms not sended from magento: SMS to could not be sent. Reason: 'Number is not set.'
I try diferent variants to type the number with same result!
3580504416737
358504416737
358 50 441 67 37
504416737 (aftomaticaly addded 358)