I am trying to perform a regex search on this date-timestamp but it is not working.

I have tried this REGEX: ^[0-9]{4}-[0-9]{2}-[0-9]{2}T[0-9]{2}:[0-9]{2}:[0-9]{2}(.[0-9]+)?([Zz]|([+-])([01]d|2[0-3]):?([0-5]d)?)?$

This did not work, it did not populate any search result. Alternatively, I have tried [0-9]{4}-[0-9]{2}-[0-9]{2}T[0-9]{2}:[0-9]{2}:[0-9]{2}(.[0-9]+)?([Zz]|([+-])([01]d|2[0-3]):?([0-5]d)?)? and it did not populate any search results either.

Can someone please help?