May I confirm if this is this the only error message that you are seeing or if there are other errors as well? As the error message says, it seems that the phone was unreachable during this time. Have you reached out to the owner of these numbers and confirmed that they are indeed reachable?
If you see no obvious issues in reaching out to these numbers, then we would need the help of the SNS team in order to be able to investigate this further. We would require details that are non-public information. Therefore, please open a support case with the SNS team by using the following link
Please provide 3-5 fresh Cloudwatch log entries in your support case. The Cloudwatch logs must be within 48 hours so that the SNS team can investigate. If you have a list of the Danish numbers that are unreachable, provide this as well as it may help the SNS team in their investigation.
Please make sure that you post these information in the support case and not here at repost. Thank you!
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