Share with Anyone option is greyed out

Issue:  When you try to share a file from your OneDrive or SharePoint using share with Anyone, the option appears greyed out.

Resolution:

Action Plan 1

First, go to SharePoint Admin Center, then click on Sharing from the left hub menu and set the sharing option to Most permissive as shown in the figure below:

Action Plan 2

If in case it does not works so disable the option "Allow only users in specific security groups to share externally"