SD card reader won't write

I have got myself a Sandiisk UHSII Sd card reader/writer and a 1.5 meter long cable as my USB c port is on the back of the computer.
It reads fine and super fast, but it will not write or format cards, not a big problem as I only got it to get data from my camera cards, but just wondering why.

I think it may be the extension cable and yet USB 3.1 is supposed to be able to work with up to 3 metres, so very strange, I may try it directly in the back of the machine, the problem is getting to it.

Can I ask the stupid question? Is the switch for read only on the card in the correct position for writing?

It is not a stupid question, but I check that just in case and it says the card/s write protected.

I think I have solved it, I stuck the reader in the back of the computer and it worked, but i thought I would give it another go on the extension and it worked again, so the only thing I can think of is that there was some dust in the USB port and mucking around with it removed the dust.
The computer have been there for three years and the port have never been used, so it is a possibility, the machine have been moved now and again to up date and to clean the inside, but dust inside the port can happen.

Thanks for the reply, I just hope it keeps working

but I check that just in case and it says the card/s write protected.

I'm assuming this is a mistake as "write protected" means you can't write to it...

Sorry, what I meant to say was that while i knew that the cards was not write protected I slid the slider anyway and that is when I got the write protect is on notice so the computer knew when they were or was not write protected.

The speed difference for the UHS cards is amazing compared t the internal SD card reader on the computer. I was going to buy another internal and replace the old one, but decided that an external may be more useful if I ever decided to get another laptop.

I will take the internal one out at some point as it doesn't work that well anyway, it has been in there for over 8 years.

The SD Cards seem very expensive. Can I ask what device you are using the card in?

In reply to a post by broadband66:

The SD Cards seem very expensive. Can I ask what device you are using the card in?

A Panasonic lumix G80, this one.
Some are expensive, but it depends on what you get, I use Lexar cards, and they work fine, and they are a pretty good price. I have two now, one that came with the camera that is 32GB and one I got myself that is 64GB. I have to get back into using it to be honest, but this pandemic have mucked things up.

I have a Fujifilm 4000 series Bridge camera and it only takes HC SD Cards. It can take a few seconds to write an HD video to the card.

I'm assuming yours will be near as damn it instantaneous?