I'm afraid we need a bit more information. Please tell us the exact steps how you can reproduce the problem.

Moreover, please make sure that there is no text in the field above the table (in the second figure) because this text is used to filter the displayed certificates.

In T5950#157442, @ikloecker wrote:

I'm afraid we need a bit more information. Please tell us the exact steps how you can reproduce the problem.

Moreover, please make sure that there is no text in the field above the table (in the second figure) because this text is used to filter the displayed certificates.

Dear ikloecker,
Thank you very much for your reply.

I confirmed that I did not put any text (no filter) when I try to encrypt for others.

The steps to reproduce the problem are shown as following:

1. as you see, I have two certifcates in the main window

2. then I click the encrypt/sign (in above window), choose the file that to be encrypted, then I came to the windows like this

3. then I would like also encrypt for the second certifcate I have in the main window. So I click the red cycle above.

4. I came the window below. As you see, there is no addtional certificate that I would like to use.

Best Wishes,
Geng

Please check the 2020 certificate by using the details dialog. Has it a valid encryption subkey?

In T5950#158024, @werner wrote:

Please check the 2020 certificate by using the details dialog. Has it a valid encryption subkey?

Dear Werner
Thank you very much.
Indeed, the 2020 certificate has expired subkey, and I had to renew the subkey to get it work.
Best,
Geng

Thanks.

Maybe we shouldn't exclude expired or revoked keys from the list so that people can still choose them. Of course, those keys wouldn't be accepted to be used for encryption, but it would help people to find out why the keys are not acceptable.

But only with an option - in general showing expired keys is annoying. For revoked keys the situation is different in case of a compromise - but many users revoke old keys anyway and we don't make use of the revocation reason. If we would consider the latter the UI/Support would be more complicated than useful.