Once there is an error on a skuid page then I am unable to select any data(lookup values) or render

I have a skuid page where on save, I call apex code. So once the page data is filled and saved and if there is any exception on save,then neither can I select any value in the lookup fields in the same page nor can I re-render components.

Are you putting your Apex call in a jquery deferred promise block so that you can be assured of success, and appropriately handle errors in the Asynch Apex process?  
More information is here: https://community.skuidify.com/skuid/topics/block-ui-and-show-message-until-sforce-connection-remote…  or in other posts on the community.