Error when deploying app at

Does anyone have an update or any ideas?

I have this issue when deploying via a GitHub Action. When I use an older docker base image (rocker/shiny:4.2.0) I get
Error: HTTP 426 GET The rsconnect package is out of date.

With a later image (rocker/shiny:4.3.1) I get the pre-flight validation failure mentioned above.

I also tried explicitly installing cli, rsconnect, and renv in the docker image, doesn't help.
The deployment from my local environment with deployApp(...) first fails with

Error: Unhandled Exception: Child Task 1329944255 error: Unhandled Exception: 599
In addition: Warning message:
package ‘remotes’ was built under R version 4.1.3

...but on a second attempt it works (?). I still didn't get it to work again using the Dockerfile, and it was working some weeks ago.

These issues are related:

Any help is appreciated!