With online conversion mode, the migration will fail with error Unable to download the config from the F5 host when using a remote authentication account.
This issue is seen even after the remote user account has Advanced Shell option enabled for the user on F5
https://techdocs.broadcom.com/us/en/vmware-security-load-balancing/avi-load-balancer/avi-load-balancer-conversion-tool/2-7-1/troubleshooting-albct-issues.html
Avi Conversion Tool with version 2.8.1 or lower
We will be fixing this issue in a future release of Avi Conversion Tool.
Workarounds:
With online mode, use a local user account and not a remote user account.
OR
Use offline mode with the F5 config file.