The product that was requested doesn't exist. Verify the product and try again.

[DegrizNet]

Hello,

in logs I see errors like this. What could be wrong?
[2021-05-19 08:06:13] main.ERROR: Omnisend\Omnisend\Model\EntityDataSender\Order: The product that was requested doesn't exist. Verify the product and try again. [] [] [2021-05-19 08:06:13] main.ERROR: Omnisend\Omnisend\Model\EntityDataSender\Order: The product that was requested doesn't exist. Verify the product and try again. [] [] [2021-05-19 08:06:13] main.ERROR: Omnisend\Omnisend\Model\EntityDataSender\Order: The product that was requested doesn't exist. Verify the product and try again. [] []

[Daimyo7]

I have a ton of logs about this issue and I have recorded 83K of them since installing this.
What is this error for and would it be fine to ignore the error or remove that logged event.