
Hi @Yordi van Eijk , welcome to Q&A forum!
As you are not SharePoint admin, are you creating sites from the SharePoint start page?
Per my test I am not able to reproduce you issue. Did it suddenly become inaccessible after some operations?
Please try to use privacy mode/clear cache/change browser to test whether it works. And you could also try to create another new site to compare the result.
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