Hello,
During a dry race, you must use 2 different types of
dry tyres. During the race, you only used one dry tyre (Wet tyres do not count, so you only used Hards)
2-tyre rule: You will need to fit two different dry compounds during a dry race. If it rains at any point during the race, the rule will be automatically disabled. If a car doesn’t follow the rules it’ll result in an automatic Disqualification / DSQ on the results and any points scored will be deducted.
This quotation has been taken from the "League Rules Guide" -
https://igpmanager.com/forum-thread/48988