Multisite fails to upgrade the network

I am getting this error when trying to upgrade the network:

https://businessikast-brande.businessr.dk

Warning! Problem updating https://businessikast-brande.businessr.dk. Your server may not be able to connect to sites running on it. Error message: SSL: no alternative certificate subject name matches target host name 'businessikast-brande.businessr.dk'

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The main domain is https://businessr.dk

Can anyone help?

Thanks :slight_smile: