Glide is not sending Login Codes from particular app

Glide is not sending authetification pin to users.

Happens in a particular app, no mail with login pin will be sent to users.

Other apps in my team are working.

I have checked the correct settings with mail column in user table…

Also personal and company´s spam filters work probably. Not detection of incoming mail elsewhere in the organization.

Please help, as user are not able to login.

Thank you.