I feel like "Because of the traffic, we were late" should be accepted here

We are late because of the traffic jam.

"We arrived late because of the traffic" should be accepted too I think.

Due to traffic congestion,we are late.

"We were late because of traffic," seems pretty good to me.

The English sentence sounds wrong. "We are late because of the traffic", "We are late because of the traffic jam" was marked wrong as well. Should it not be correct?

We were late due to traffic

Because of the traffic JAM, we are late.

Because there was traffic

traffic jam - better than simply traffic, as traffic can be light or heavy. It does not necessarily impede travel

Duolingo offered me the word "jams" in the word bank yet did not accept the sentence "Because of the traffic jams, we are late," despite "traffic jams" being provided as a definition for 堵车 . Surely, this should be accepted?

"We are late due to traffic" is very natural