If I issue a challenge to a correspondence game to a friend, the challenge disappears if I log out, so my friend does not get the chance to accept a challenge unless I am still online. Therefore, it is very difficult to start a correspondence game with a friend. I recommend that correspondence challenges stay active until either the issuing player cancels the challenge, or the challenged player accepts or declines the challenge.

I had a similar issue, and I found this workaround:
- save the browser URL on the challenge page,
- you can send it to them as a message - the challenge should remain active, even if you log out.

Please note only, the in-PlayStrategy messaging does not resolve the link well, to avoid that problem, you could add a character at the beginning of the link, e.g. _https://playstrategy.org/McD37J8V

Hope this helps!