Invited a speaker to talk at a conference which is part of a bigger conference and the parent organizers rejected their participation. What to do now?

Question

I am organizing a volunteer academic conference as a part of a larger conference at a top university (let's call it X). Organizers are required to invite speakers to talk about their research in a certain field and then send their agendas to the organizers of the parent conference at X for review. I asked the speakers to give me a rough description of their talks for review. And it happened that the parent organizers disapproved of one of the speakers I invited (gave me an unexpected final no, saying that the speaker's topic is out of the conference scope).

So I had to apologize to the invited speaker but, they were deeply offended and told me that their abstract was general and that I should have told them to provide more details, in the same email they provided me with more details about the talk then, I contacted the parent organizers at X again and they apologized and approved them.

My question is how to apologize to them for this horrible mistake. The speaker is an esteemed professor and I am a student.

I thought of saying:

Dear Professor ...

Thank you very much for your clarification and for sending us more details about your talk.

X often reviews the agendas/content of the smaller events associated with them. We contacted them for the unexpected mistake in their feedback to us and they apologized for interpreting your talk's content as out of the defined scope. We hope you accept their apology and ours too.

And we would be very happy and honored if you are still interested in giving a talk at our conference.

Best regards, ...

If you are in this professor's shoes what would you think of my email? and is there a way to make it more polite?

Thanks

EDIT: The first reviewer decided that the talk's content is out of the defined scope and didn't leave an open door for further discussion. He told me "I am sorry, I am unable to approve them as their talk's content is not in alignment with our requirements. I hope you could host them at another event" then after the professor's reply, I went to someone who is superior to the first reviewer and got the acceptance and the apology.

Answer 1

The e-mail you propose is basically fine; there is no magic incantation for talking to professors or anyone else.

I do propose making it shorter and clearer, like so:

Dear Professor ...

I followed up with X as you suggested and spoke with a more senior reviewer. This person quickly realized that a mistake was made and your talk is indeed in scope for our conference. They have asked me to convey their apologies for the error. I also apologize for my part in this debacle.

We will be very happy and honored for you to give a talk at our conference. Please do let us know if you are still willing to do so.

Best regards, ...