It requires a lot of force to plugs thing in Vietnam. All plugs I have found look like European ones with two round prongs but do they use a different standard than Europeans?
In many places there were also ones with thin vertical slots which look like North American plugs and, even then, I have had the same difficulty in all 6 hotels and 1 boat where I have tried.
Here is a typical hotel plug in Vietnam:
What it looks like to me is something designed to take European and North American plug but is it? Or is there Vietnamese-specific plugs and adapters?
None of my plugs fit easily and I cannot get the USB charger to plug in because the retractable prongs get pushed back in, so I've been plugging a laptop just o charge my phone.