Looks like this is coming from other sources as well.
Nancy Pelosi refused to allow White House officials access to the House floor for a State of the Union walkthrough
The president is permitted to enter the House chamber at any time....Whether Trump could just get up on the dais and start delivering his State of the Union address is another question...... Nothing could physically stop Trump from speaking in the House chamber, but there is a strict set of rules governing what is allowed to take place on the floor....In order for someone to deliver formal remarks in the House of Representatives, the chamber must be “in session,” which is at the discretion of the speaker.