spark sync problem with iphone

spark sync problem with iphone

Hello,
I am using the spark application on iphone 15 pro max and 16 pro max.
After several days of installing the account on spark i dont get notifications on new emails, i have to open the app in order to receive the new emails.
After sending email to spark they answered me that : This error indicates that some of our server's IP addresses were blacklisted by your mail provider. 
and i have to solve it with my provider(zoho)
Is anything i can do?