Durig the following step:
7.1.5. Go back to your Auto Scaling group and then to **Details** > **Launch template** > **Edit**. In the **Version** drop-down, now you can select the `Latest` option and click on **Update** button at the bottom of the page.
I get the following error message:
You are not authorized to use launch template: lt-073ed9eb92ff688ea
Hello @maciejmax, I tried to recreate the error and in 7.1.4 if you select t2.nano instead of t3.nano you get this error at the bottom. Could you try selecting t3.nano instance type from the dropdown. Thank you.
Hello @Georgios 
Shame on me! I was wrongly using t2.nano instead t3.nano.
Thank you for looking at it with a fresh eyes
Glad its fixed now, cya
Ah, I had the same issue, and your solution worked, @Georgios . Thanks!