Unable to disable email confirmation

I need to disable email confirmation for new user because resending confirmation email is not possible. This may cause my users to be stuck and have bad experience with the app. When I disable this on Backendless admin panel I get a popup about backend being incorrectly setup and that I need to contact developer. Can you help me with this? I tried changing identity to name or other fields in case it was blocking this disable feature but no change.

What happens when you click the “Test” button located at Manage > App Settings > Email Settings?

I get error could not connect to host. I am using gmail account for this and I enabled access for unsafe apps there. It worked some time ago.

What is your application ID?

Application ID: 9BD8EE9D-DF65-2CC1-FF65-52CF0162EC00

I believe it is incorrect to use IP address for SMTP host when you use gmail. See the instructions here: https://support.google.com/a/answer/176600?hl=en