Apt-get update failing

Build server for creating an image for the Xavier stopped working this morning when trying to update from the Nvidia repositories (retried several times over the last few hours):

Get:6 https://repo.download.nvidia.com/jetson/t194 r32.5/main arm64 Packages [14.2 kB]
Err:6 https://repo.download.nvidia.com/jetson/t194 r32.5/main arm64 Packages
  File has unexpected size (13379 != 14202). Mirror sync in progress? [IP: 23.38.191.152 443]
  Hashes of expected file:
   - Filesize:14202 [weak]
   - SHA256:ed9bb93111560bf606082a4ddac89c27399ea748b8bb8482aaaa99e7dd174556
   - SHA1:2c26b05f770b5ae65de7ebd3d16b24a270c91353 [weak]
   - MD5Sum:441fc79065602616a640f2a10094b931 [weak]
  Release file created at: Wed, 17 Mar 2021 03:22:00 +0000
Fetched 18.9 kB in 5s (3547 B/s)
Reading package lists...
E: Failed to fetch https://repo.download.nvidia.com/jetson/t194/dists/r32.5/main/binary-arm64/Packages.gz  File has unexpected size (13379 != 14202). Mirror sync in progress? [IP: 23.38.191.152 443]
   Hashes of expected file:
    - Filesize:14202 [weak]
    - SHA256:ed9bb93111560bf606082a4ddac89c27399ea748b8bb8482aaaa99e7dd174556
    - SHA1:2c26b05f770b5ae65de7ebd3d16b24a270c91353 [weak]
    - MD5Sum:441fc79065602616a640f2a10094b931 [weak]
   Release file created at: Wed, 17 Mar 2021 03:22:00 +0000
E: Some index files failed to download. They have been ignored, or old ones used instead.

Problem has resolved itself.

Correction, this problem is coming and going at random.

It seems the network issue at your side.