Our APP is only built to hand transactional email volumes from SendGrid. This is due to a few limitations on the SendGrid and HubSpot APIs.
This issue often occurs if you are using SendGrid to send to large marketing lists it will cause the event processing to spike on our end and will cause issues and delays with processing.
To resolve we offer the following options:
Only send critical events for us to process such as clicks and opens. These only occur when a email recipient performs an action which greatly cuts down on the the number of events if you are doing marketing sends.
Create a sub user account on SendGrid to seperate out your marketing and transactional email sends. This new account will then only process and send these events to us for processing.
Now only a limited number of emails will be sent to Mail Sync for processing.
We can uncap your billing. Currently we have a fair use billing cap at $100per month.
This is only a good fit if you are sending to smaller lists via SendGrid as the costs can add up quickly.
Note this can cause very high billing if you are sending to large marketing lists. We can also not guarantee processing of subject lines due to API limits on the SendGrid side.