I can open any file on a smb://user@server/path/ except any pdf. Okular gives the error:
"Could not open smb://user@server/path/to/file.pdf.
Reason: Access denied to smb://user@server/path/to/file.pdf.
I'm new to Kubuntu. The first time I tried to open a pdf on the other networked PC, it asked me for credentials. I can't remember exactly the series of dialog boxes that came up but apparently I selected the wrong encryption protocol (gpg) and do not know how to correct this problem. This is a related post:
https://forums.opensuse.org/showthread.php/518766-Okular-and-Samba-Server
Is there something I can do in Kwalletmanager? I can see a map to the smb PC on the network.
Thank you.

I also cannot save pdf's to some folders.
Pdf's that I cannot open have:
Ownership -
User: geoffrey
Group: geoffrey
Access Permissions -
Read
User x
Group x
Others x

Other files (.doc, .xls) that I can open have the same ownership and permissions.

OK, I got it to work from the command line: okular 'smb://username:pwd@coolermaster-pc/E/Work Files/Yupin/DropBox/Accounting(1)/389-LA-EDF.pdf' Now, how can I get it to work from Dolphin?
I thought it might have something to do with kwallet (where the networked computer username:pwd is stored) but I disabled the kwallet system and I'm still denied permission. In Dolphin, if I add the password to the folder address, I can access the pdf file (smb://username:pwd@server/path/to/folder). I can access any other file without adding the pwd).

I decided to try to open a file using the open file dialog box from within Okular (instead of clicking on the file in Dolphin). I first clicked on the network drive, a dialog box opened asking for my username and pwd (for the network): I checked the "remember my password" box gave my username and pwd. That dialog box closed and a new one open saying KDE Daemon was trying to do something with Kwallet and needed a password to access that. I gave it. So, now I can access the network pdf files from Dolphin or from within Okular. There doesn't seem to be any change to the kwallet entries.