For the last few days, if you were trying to use the custom date option from settings then you weren’t able to do it. The calendar dialog box won’t let you select any dates of your choice. According to Google, this was a bug and now it is resolved.
Tweet By Google Search Liaison
We're aware that using the Custom Range option to restrict search results by date may cause a browser's tab to freeze. We hope to resolve this soon. In the meantime, the before: & after: commands can be used for date restriction. More here: https://t.co/5l4HON1pxB
— Google SearchLiaison (@searchliaison) January 19, 2021
There were a lot of complaints regarding the same issue on the Google Web Search Help forum. Google has not given any fixed or estimated time to fix this issue. But later on this morning, they announce that they have fixed the issues. Now users can select the date from the custom date range option.