There is a known issue with the refresh facility that will be addressed in the v27.1 release (see my response in this disucssion: https://www.sagecity.com/gb/sage-50-accounts-and-sage-50cloud-accounts-uk/f/sage-50-accounts-and-sage-50cloud-accounts-uk-general-discussion/158970/sage-50-v27---excel-ingregation---refresh-no-longer-working) but I can't think of any good reason why nothing would happen when using the add functionality. Even if you had no data (unlikely to be the case) I'd still expect to see a select company screen, just with no companies displayed by default. For nothing to happen the text would have to be considered not equal to 'Add Company...' and from your screen shot it blatantly does so I'm a little bit stumped on this one at the moment.

The v26 EIR plug in would not be able to access v27 data but we have made one last version of the legacy EIR available for download (again see my response in the post linked above for details) and this should be capable of accessing v27 data so could be used as a potential workaround.

We have subsequently found a minor issue where if you go to add a company but cancel when the add company form shows then the drop down text does not revert and you can no longer add a company. A fix for this will be included in the v27.1 release. In the meantime the simple workaround for this issue is to close and reopen Excel.