Hi, I've been making DVDs and Blu-Rays in DVD Architect the past few years and it's been a massive pain. I feel as though I've run into every issue I possibly can, so I figured I'd share some of my problems and solutions with you so you don't have to go through the trial and error I've had to. This is all for version 5.0, but may apply to other versions, who knows.

PROBLEM: Whole screen blinks when text is on screen.
CAUSE: Bit Rate is too low.
SOLUTION: Up the bit rate

PROBLEM: An unknown error occurred, ending your prepare and outputting nothing.
CAUSE: Most likely file format issue. It would get hung up on MP4 files when rendering but not MOV. Not sure why.
SOLUTION: Don't use MP4. Just output something like MOV and let DVD Architect compress it itself.

PROBLEM: DVD Architect attempt to find discs to write to when you press 'Make Blu-Ray" or "Make DVD". This causes it to freeze.
CAUSE: DVD Architect attempt to find discs to write to when you press 'Make Blu-Ray" or "Make DVD". If you have any drives/discs attached it may get overwhelmed, causing it to freeze.
SOLUTION: Unplug your drive/disc before preparing files.

PROBLEM: Everything outputted as black.
CAUSE: Memory issue. When opening about 6 or so files it uses up all the memory and outputs all menus and such as black. DVD Architect 5.0 can only use 2gb of RAM.
SOLUTION: Patch the .exe with the 4gb Patch from ntcore.com. This allows the program to use 4gb instead of 2gb. Bless mmediaman on the Vegas support forums. https://ntcore.com/4gb-patch/

PROBLEM: Videos outputting frozen on a single frame (the beginning one)
CAUSE: I believe a render issue. Tends to happen with videos that have very little movement in the first few frames so I'm guessing it just assumes the whole thing is like that.
SOLUTION: Delete them from the project and reimport. It should render them better. It helps to open them before rendering and scrub through a few frames first to load it into memory. I think. Might be placebo.

PROBLEM: Disc plays on PC but not on PS4.
CAUSE: This could be a file structure issue if you're not using a proper program, but should output fine if using DVD Architect. Is most likely a speed issue.
SOLUTION: Output at 4 instead of 6x for maximum compatibility. If this fails use the program IMGBurn to burn your disc with the prepared files from DVD Architect. But the BDMV and CERTIFICATE folders into the source. Click options tab and make File System UDF and UDF Revision 2.50. You can add stuff like Volume name and such in labels under UDF and other labels.

In short, this is how I made my Blu-Ray disc. 

INPUT: .MOV files encoded in H.264 with Linear PCM audio at relevant frame rate (23.976). 

DVD Architect rendered everything out to proper format (end result is m2ts files)
Bit rate 35 or something (this overkill as 25 bit should look just fine).
4gb patch from ntcore.com for increased memory.
Prepared folder from DVD Architect. 
Throw folders (not disc image) into IMGBurn under UDF 2.50 at 4x. 
Burn.
Test.
Done.

Hope this helps!