I own a Galaxy Tab S4 that I bought 2 months ago.
I inserted a SD card with 128GB of capacity and it's been working smoothly for two months.
However, after one week of having the device idle, I used it again today, and I'm not able of accessing to the SD card.
The only message that I get is: "Security policy prevents use of external SD card"
I've been reading one old post of 2017, and I've reset app permissions, but it's useless.
I have the OS up to date with the last updates.
What else can I do?
I found the solution. A few days ago I installed my Company Portal and that was the reason.
I switched it off from Device Admin Apps, and now everything works smoothly.