Export Adobe Lightroom

Hello dear community.
I have the problem that Lightroom doesn't allow me to write to an external hard drive. This morning I was able to export photos as jpeg to an external hard drive and into the designated folder. I imported a new batch of images and now I can only export them using the short cut to the folder generated by Lightroom on my internal hard drive. But no longer specifically in specified folders. I have already allowed all hard drive access rights in the settings of my Mac Book Lightroom, but nothing happens. I'm currently in a project with a deadline of Monday, May 27th, 2024. Please help me!!! What should I do?