554 5.3.4 Content conversion limit(s) exceeded

Could not send mail from PowerBI to local mailbox using SMTP receive connector. There is EventID DELIVERFAIL: "STOREDRV.Deliver.Exception:ConversionFailedException; Failed to process message due to a permanent exception with message The content conversion limit has been exceeded. ConversionFailedException: The content conversion limit has been exceeded. [Stage: PromoteCreateReplay]'" in Transport log.

How/where could I check/set the content conversion limit? Is there some other log, where I can find detailed information about this?

Message size is 1.3MB, maximum message size in connector is 20MB

Exchange 2019 CU 14

Thanks.