"I want to play tennis, but I caught a cold."

Translation: 我要打网球，但是我感冒了。

[GustQuest]

I omitted the subject in the second clause and got marked as wrong
我要打网球，但是感冒了。
I think you can do that in Chinese when the subject can be inferred from context, or the previous sentence

[JonnyEightyFour]

I'd also be interested to know if with context, it's okay to drop the second 我

[another-called]

I think typically, you'd want to use 想 instead of 要 in this case.

[DuDaoge]

Should also allow 可是 as an alternative to 但是。

[Paul165368]

I know we hat that in previous lessons, but I am kinda wondering how 感冒 means "caught a cold".
I thought:

感 means feels, sense

冒 means risk, bold

感冒 means caught a cold
(Or literally "sense risk/ feel sickly" ）

How is this possible?