Upgrade assistant stops at 80%

I'm trying to use the upgrade assistant to upgrade indexes created with older versions of elastic stack (version 6).

I started the upgrade process with version 7.10. And then I upgraded to 7.16.2. In both versions I'm getting the same result. the message "This step was paused due to a Kibana restart. Click 'Resume' below to continue."

Kibana doesnt look like is restarting, because I'm able to use it without interruption during the entire process.

How can I find out whats going on?

Thanks!

Can you please post your Elasticsearch and kibana logs please?

Thank you,
Bhavya