EasyMail Issues!

Hi,
We’re having trouble with sending email via a ALO EasyMail Newsletter plugin. Up until about a month ago, this had not been a problem. (we have the very latest update: Version 2.8.1 as of 3/11/2016)

Clues:
Newsletter is sent, but only to 56% of recipients> here’s the report:
Total recipients Sendings done Sendings succesful Sendings failed Unique views Clicks
537 537 302 235 530
100% 100.0% 56.2% 43.8% 9.9% 0%

Notes:
Just fyi: We take sending our newsletters seriously and wouldn’t ever intentionally send too many emails too fast. (Our list is only 550+ email addresses)

Hosting support shows that no emails are being sent (according to their logs)

Our domain: http://home-automation-services.com/

Can you please help?

Thank you,
Kerry