If you encounter the error below while following the instructions in How to Publish a Narrated PowerPoint Presentation with OneDrive you can attempt to resolve the problem by taking these steps.
“We can’t play the media in this presentation because it’s larger than the file size limit set on this service.”
On a windows computer open the narrated PowerPoint.
Click File at the top left of PowerPoint.
If it is an older PowerPoint file you may have to first convert it by clicking Convert next to Compatibility Mode.
Once converted, or if no conversion was necessary, click Optimize Compatibility. This begins the optimization process and the Optimize Media Compatibility window will open indicating its progress. The time taken to complete this process will vary deepening on the amount of slides and length of narration.
Once the optimization has completed, save the file and upload it to OneDrive again.