i resolved this myself by changing deprecated code in given errors
But ultimate member is showing follwoing error after activation. Before activation of Ultimate members there is no such error. review this notice
Notice: add_submenu_page was called incorrectly. The seventh parameter passed to add_submenu_page() should be an integer representing menu position. Please see Debugging in WordPress for more information. (This message was added in version 5.3.0.) in /home/lightess/eregistration.lightessystem.org/wp-includes/functions.php on line 4986
