Zoho can't send emails in Spanih properly it always cuts off (vowels with accents and ñ leter)

Zoho can't send emails in Spanih properly it always cuts off (vowels with accents and ñ leter)

Hello,

- Zohomail can't send emails in Spanih properly  it always cuts off (vowels with accents and ñ leter)

- I check my spelling before I send out my emails in spanish, but the recipient gets questions marks instead of vowels with accents and the ñ leter.

How to solve this problem?