Can’t access to authentificator on my older phone - so I can’t connect to some personal accounts

If Microsoft Authenticator was not backed up from the old phone, the saved entries cannot be restored from that phone backup.

For personal third-party accounts such as Instagram, the one-time password codes are only available after restore if a backup existed. If no backup exists, the account must be added again in Microsoft Authenticator, or recovery must be completed with that service’s own account recovery options.

For Instagram and similar personal accounts:

1. Use that service’s backup sign-in method, backup codes, email, phone verification, or account recovery flow.
2. After access is recovered, remove the old authenticator setup in that service’s security settings.
3. Then add the account again to Microsoft Authenticator on the new phone.

If the issue is with Microsoft work or school accounts and the old phone is no longer available, an admin must reset the multifactor authentication settings so registration can be completed again.

If restore failed for reasons other than missing backup, Microsoft guidance says the accounts can be added again. On iPhone, backup and restore also only works on the same device type, and requires iCloud Drive, iCloud Keychain, and iCloud Backup for Authenticator to have been enabled.

References:

• Restore account credentials from Microsoft Authenticator
• Back up your accounts in Microsoft Authenticator
• Transfer Microsoft Authenticator account entries to a new phone
• I can’t login to my instagram account - Microsoft Q&A
• Can't use Azure Multi-Factor Authentication to sign in to cloud services after you lose your phone or the phone number changes