How to upload a previously used key for encrypted form?

I have asked this question before, but have not gotten an answer. I created a new form and now I would like to make sure it is encrypted. When I select YES for the option to Encrypt my form, a box pops up asking me to confirm my password before getting a public key. I should be getting a popup asking whether I want to use a key I have already or do I want a new key...I have included a screenshot below...

If there is anyone out there who knows what I am talking about, please let me know! I have deleted the key previously used thinking it was corrupt. The treasurer emailed me the key and now I have it saved in my downloads. I am still getting the same message. I really can't afford to throw away another form...it costs me every time I do!

I have not provided a URL because the page is not live yet. 

Hello, 

When you are setting your form to be encrypted, the option to choose which key to use is shown after you enter your password:

Is it something you were asking about?

We will wait for your response. Thank you!