Is this a correct way to use the word "however"? [closed]

We apologize; however, we are unable to process your request.

I'm sure however is not the correct word to use here. I feel like a causal conjunction might be better. I'm still trying to understand the limitations of however.

You use "however" to show a contrast.

If you apologize because you can't process the request, then the combined wording of the two sentences is not proper because there is no contrast.

• We apologize for being unable to process your request.

If you apologize for some other reason, for instance because you couldn't reply soon enough and that the person is complaining about that while maintaining the request, then this formulation using "however" is not very good. It is better to be specific about the reason for the apology.

• We apologize for not having replied promptly to your request; as concerns this request, we are sorry to inform you that we are unable to process it.

You might then use "however" if contrasting with this bad situation there is the perspective of doing better in the future.

• We apologize for not having replied promptly to your request; as concerns this request, we are sorry to inform you that we are unable to process it; however, would you still be maintining your request for one more month, past this delay we will be able to process it.