can't download large files from MS Sharepoint

I am unable to download large files from an MS Sharepoint account in Firefox. Small files are fine (less than 100MB). Large files download fine if I use MS Edge browser but I don't want to have to use Edge unless absolutely necessary. Using Firefox Troubleshoot mode doesn't help. Clearing the cach/cookies etc doesn't help. When downloading a 600MB file, the download repeatably fails around 90-100MB. My OS is Linux Mint xfce64. Obviously MS doesn't like firefox for some reason, even in Troubleshoot mode. thanks in advance for any help.