Trying to share drives between two PCs. Hitting permission problem?

Hi /r/networking,

We have two workstation PCs running Windows 10 Pro that we're using for video editing, both with 8TB hard drives in addition to their SSDs. We're on a secure network on a R7800 router, connected wirelessly.

We want to make each PC able to access the other's 8TB hard drive so we can transfer footage and stuff between the two computers, and we're most of the way there but can't quite figure out the rest. We're hitting a permissions error.

https://i.imgur.com/jLYOvDK.jpg

Not sure what to do from here! If anyone can assist that'd be great. Networking isn't really my forte...

Thanks!