# Send SMTP Mail fails with Error 'Unknown"

**URL:** https://community.ciphermail.com/t/send-smtp-mail-fails-with-error-unknown/1036
**Category:** Android S/MIME
**Created:** [November 29, 2025, 8:36pm UTC](https://community.ciphermail.com/t/send-smtp-mail-fails-with-error-unknown/1036 "2025-11-29T20:36:37Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![sirtet](https://dub1.discourse-cdn.com/flex017/user_avatar/community.ciphermail.com/sirtet/32/242_2.png) [@sirtet](https://community.ciphermail.com/u/sirtet)
#### Post date: [November 29, 2025, 8:36pm UTC](https://community.ciphermail.com/t/send-smtp-mail-fails-with-error-unknown/1036/1 "2025-11-29T20:36:37Z")

</div>

Thanks for this App.

A little feedback:

I struggled with the setup, because of a cryptic error message, would be nice to improve that:

When i first tried to send a Message, after entering the Keystore password, the App showed a toast

‘Sending message…’

And immediately after, another one that said

‘Unknown’

I guessed my config. was the Problem, but i copy pasted the SMTP Settings from Thunderbird, so i did not see how it could be a config error.

After a while, i DID find a typo that somehow got in…

So, making SMTP errors more explicit might help others in the future.

PS:

I enabled the ‘debug’ checkbox in hope to get more output, but no luck…

What does it do? Found nothing about it in the reference.