I have made a test on my side and don't have the issue that you mentioned. I think this issue may be related to the License your Microsoft Flow belongs to.
If the License of your Microsoft Flow is Flow Free, I afraid that some connectors would not be available to your Microsoft Flow. Please consider take a try to upgrade the License of Microsoft Flow into Flow forOffice 365 license and Flow for Dynamics 365 license, Flow Plan 1 license or Flow Plan 2 license, then try your flow again to check if the issue is solved.
More details about different licenses of Microsoft Flow, please check the following article:
In addition, you could consider take a try to access Microsoft Flow Site in other Region, such as, Microsoft Flow Site in Asia Region. Please take a try to access Microsoft Flow Site in Asia Region with the following link: