Hi larosaf,
Thank you for participating in the Apple Support Communities. We understand you're having trouble with file sharing. This article can help make sure everything is set up correctly: Set up file sharing on Mac.
"You can share files and folders with others on your network. You can share your entire Mac with everyone or allow specific users access to only certain folders.
Set up file sharing
- On your Mac, choose Apple menu
> System Settings, click General 
in the sidebar, then click Sharing on the right. (You may need to scroll down.) - Turn on File Sharing, then click the Info button
on the right. - To select a specific folder to share, click the Add button
at the bottom of the Shared Folders list, locate the folder, select it, then click Add.
The Public folder of each user with an account on your Mac is shared automatically. To prevent a folder from being shared, select it in the Shared Folders list and click the Remove button.
4. Control-click the name of the folder, choose Advanced Options, select desired options, then click OK.
See Set advanced file sharing options.
5. By default, any user set up on your Mac in Users & Groups settings can connect to your Mac over the network. A user with an administrator account can access your entire Mac.
To give only specific users or groups access to a folder, select the folder in the Shared Folders list, click the Add button at the bottom of the Users list, then do one of the following:
- Add users or groups from all users of your Mac: Select Users & Groups in the list on the left, select one or more names in the list on the right, then click Select.
- Add users or groups from everyone on your network: Select Network Users or Network Groups in the list on the left, select one or more names in the list on the right, then click Select.
- Add someone from your contacts and create a sharing-only account for them: Select Contacts in the list on the left, select a name in the list on the right, click Select, create a password, then click Create Account.
6. To specify the amount of access for a user, select the user in the Users list, click the pop-up menu next to the user name, then choose one of the following:
- Read & Write: The user can see and copy files to and from the folder.
- Read Only: The user can view the contents of the folder but can’t copy files to it.
- Write Only (Drop Box): The user can copy files to the folder but can’t view its contents.
- No Access: The user can’t see or copy files from the folder.
7. Click Done.
Set advanced file sharing options
Use advanced file sharing options to set the protocol and other options for each shared file.
- On your Mac, choose Apple menu > System Settings, click General in the sidebar, then click Sharing on the right. (You may need to scroll down.)
- Turn on File Sharing, then click the Info button on the right.
- Control-click the name of the shared folder, then choose Advanced Options.
- Select advanced options:
- Allow guest users.
- Only allow SMB encrypted connections.
- Share as a Time Machine backup destination.
5. Click OK, then click Done."
You may also want to temporarily disabled any security software you may have installed on both Macs and see if the issue persists after doing so. This type of software can sometimes affect network connections.
Take care.
