Issue
Customers may receive warning messages when sending to Distribution or Group lists that exceed a specific number. For example, customers sending in Outlook may receive a warning that a contact group contains more than 1000 recipients and to please switch the tracking type to Overall instead of Individual sending to lists that exceed the upper limit.
Reason
Customers receiving this message in Outlook or Gmail are receiving this warning because they exceed the limits imposed by Microsoft or Google for sending to Distribution lists through an add-in.
ContactMonkey has outlined the various sending upper limits in a helpful article that advises about them and multiple options to overcome them.
Solution
Customers can consult the ContactMonkey upper limits article and choose the appropriate combination that will be allowed for the list size. For example, when hitting the 1000 limit in Outlook, this is likely due to utilizing the COM Add-In for legacy/classic Outlook.
Customers in this situation should upgrade their Outlook and utilize the more modern interface. For example, some Outlook versions allow customers to switch to the Modern Outlook interface, and then customers can install and use the ContactMonkey Web Add-In for Modern Outlook or utilize Microsoft's Outlook Web App with ContactMonkey's Web-Add In as an alternative when sending to large lists.
In other situations, customers may be hitting the 2000 limit in Gmail. They may need to consider utilizing ContactMonkey's Email at Scale option to send to more extensive lists.