Hey @Csmc, I hope you're doing well. I'm sorry to hear that you're having trouble with the Samsung Members app.
Could you please provide the screenshot of the error so that I can better assist you?
I look forward to hearing back from you.
Hey @Nannyogg06, I hope you're doing well.
This community is for US based Samsung devices. Are you using US Samsung Galaxy S20 Ultra's in the UK? If so, this might be the issue. US based units cannot download or install the international version of the Samsung Members app. Only the US version of Samsung Members can be installed on Snapdragon units in the US.
If your device is the Exynos model, you can download the international version of Samsung Members directly from the Samsung Galaxy Store. You can find it by pressing this link: http://apps.samsung.com/appquery/appDetail.as?appId=com.samsung.android.voc&cId=000003596846
I hope this helps. Take care.