Hi @stejus,
Thank you for reaching out! The WP Mail SMTP is designed to work whether your users are logged in or not. However, I have a couple of ideas on what might be causing this issue:
1. Caching Plugin: If you have a caching plugin enabled, try turning it off temporarily and test the form again. Sometimes, the cache can prevent the form from processing correctly. If this resolves the issue, you may need to adjust the caching settings to exclude the form page.
2. Form Configuration: Check the settings of the form itself. It may be set to only allow submissions from logged-in users.
I hope these suggestions help you troubleshoot this issue further.
Thanks!