With reference to the current site setting limit of 50mb
Configure file upload size
By default, the file size is set to 10 MB. However, you can configure the file size to a maximum of 50 MB by using the site setting SharePoint/MaxUploadSize.
Please can the limit be increased to something less limiting such as 500mb of 1Gb?
With SharePoint Online currently allowing up to 15Gb files to be uploaded, 50mb is way too restrictive.