We'll need to have a look at the output_log.txt to see what's happening and where the problem is. Steam isn't great for support as we can't attach files here, so I will need you to make a post on the official support & bug forum here:
https://forum.paradoxplaza.com/forum/forums/support-bug-reports.879/
The output_log.txt is found in the Cities_Data folder where the game is installed. The easiest way to find it is right-clicking on the game in your Library, select Properties, find the tab Local Files and click Browse.
You can attach the log directly to the forum post and we'll have a look and see what's up.
https://forum.paradoxplaza.com/forum/forums/support-bug-reports.879/
The output_log.txt is found in the Cities_Data folder where the game is installed. The easiest way to find it is right-clicking on the game in your Library, select Properties, find the tab Local Files and click Browse.
You can attach the log directly to the forum post and we'll have a look and see what's up.