There is problem when trying to sign in to the ArcGIS Pro. It's blocked and cant sign in
Could you check the network firewall (add the URL in trusted sites of Internet Explorer) or proxy settings?
See a similar issue here
Unable to establish connection to www.arcgis.com from ArcGIS Pro? - GIS StackExchange
How is the solution???
Had same issue. In Internet Explorer, under Advanced Settings,the Use TSL 1.2 was not checked. Once checked, ArcGIS Pro opened without issue.
Mark's solution is correct. Esri stopped allowing connections not using TLS 1.2 earlier this year.
Open IE > Tools Menu (press Alt-T if you don't see the Tools menu) > Internet Options > Advanced > Check "Use TLS 1.2" checkbox > Apply
Thanks, had a user with the same issue and this worked perfectly.
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