I had the same type of issue when doing that a week ago, but my internet connection was quite bad.
I gave out because it was not important.
Have you tried to download your file using filestation from synology ?
Yes, I did try that, and originally I thought it was going to work, but it failed as well. I have tried from 2 different locations that fail (office and home). It works from the office if I use Linux, but not Windows. It also works if I go to the school where the NAS is, and connect directly to the network there.
I’m installing another Linux VM at my home, and I will see if it will transfer to that PC. The VM will be hosted on a PC that it won’t finish the transfer to. I know that SMB on the Synology was just updated, and I am wondering if there is a problem since I am 99.9% sure that I have transferred these files over Tailscale in the past to this PC.
The VM using SMB seems to be fine. Transfer isn’t actually finished yet, but it is well past the point it would have failed on the Windows host. So weird.
I can’t transfer a large file to my Windows i9 PC, running Windows 11 Pro from a Synology NAS. It starts, then slows to 0 Mbps x-fer speed after a few seconds, then fails roughly 30 seconds later.
However, I installed a Linux VM on that SAME i9 PC that it fails to transfer to, and it is working fine.
It does appear to be Tailscale related. I created another VPN from the Unifi network where the NAS is and used it to test SMB to the NAS, and it is also working fine. So the common denominator here is Windows (11?) and Tailscale.