In normal times, dropouts can’t happen when you render, unless there is an external effect in the loop.
Else there is no time constraint that could cause missing samples.
Else, this is a hardware issue, like a faulty hard drive (if you can, try the same project on another computer).
Else, this means there is a plugin with a problem.
Try to replace the plugins with some equivalent ones, eg. the Steinberg plugin set has very nice plugins. Does that make a difference, from the droupout POV?
Also, when you have a VST2 plugin with aproblem, try the VST3 version, if any. And reciprocally. But always prefer the VST3 version by default.