There are a number of different issues at play here.
First, the error "503 Service Temporarily Unavailable" will always (it seems) intermittently occur. I updated 819 movies last night. In the 90 minutes that took, there were 11 of these—causing the update of 11 records to fail. A 1.3% failure rate for a Silent mode operation is fine. But if the same error is encountered when not in Silent mode, the failure will look like any other.
Don't know what you mean by that last sentence. The 503 error is identifiable when not in silent mode because of the dialog box that pops up. In silent mode, presumably it wouldn't pop up, though I've never tried it. This new problem has no popup; it just starts to download and then quits with only the IMDb URL filled in.
This is why I recommend always using the -debug switch—so the log is available to determine the cause of any failure.
I finally figured out how to do this with the portable version of PVD. If you're starting the program with PVD_Portable.exe, pvdconf.ini will be stored in the Data folder. But PVD_Portable.exe launches viddb.exe in portable mode, and that's the program you have to apply the -debug switch to. So you have to create a new shortcut to viddb.exe with the -debug
and -portable switches. But when you do, it creates a new pvdconf.ini file in viddb.exe's folder and you lose your settings. So you have to replace that with the pvdconf.ini from the Data folder. Next time the IMDb problem happens, I'll post a log.
Second, there is an IMDb site redesign going on.
Hopefully they'll leave the old design as an optional display for a long time. I looked through it all and read about the changes and I don't see much advantage to it except for larger pictures. It breaks parts of the IMDb Movie Collection Manager Greasemonkey script as well as the TweakMDb addon, so I've set it back to the old design. Once those are updated, I'll consider switching.
