I don't have the physical copy of this game yet so there might be some weird rule of which I'm unaware. If so sorry for the bad report.
I have tried several times for days to create a game using 10 cards from the new Allies expansion. If I create 4 card slots for Event, Landmark, etc, I keep getting an error code that says "Kingdom Has Too Many Cards". I have to either reduce those slots to 2 with 10 Allies kingdom cards or keep all 4 slots and have my kingdom cards include only up to 7 Allies cards with 3 random. Either/or works but not all together.
Can you post a screenshot of your kingdom options, similar to mine?
(https://i.imgur.com/uiMM5hA.png)
That should make it easier to find out what exactly happens. Can you also say which subscription you have?
With my setup, I got 4 games in a row with no error.
Of course, note that having 10 Allies cards means 4 landscape slots is not useful. Since the game only ever looks at Allies cards, it will never produce a landscape other than an Ally.