Dynamics 365 CE - Sending bulk Emails from CRM using Server side synch with Exchange Online
We have an implementation where multiple emails get generated based on Application registrations and are sent out using a noreply Exchange Online Mailbox. In the past few days there were 30000+ applications generated and corresponding emails were being sent out at 10000 emails per 24 hour limit with loads others being stuck in Pending Send. However, today 20000+ emails were sent out in 1 day.
I would like to understand what are the limits when sending out emails from CRM if any. Are there ways to increase these limits for a specific mailbox?