Strange Upload of files issue with MacBook Pro

My system

Wifi broadband via Toob

MacBook Pro Apple M1 Sonama 14.4.1

iPhone 14 iOS 17.3.1

WordPress site 1 Hosting by FastHosts

WordPress site 2 self installed on FastHosts web host site

I used to be able to upload media files to WP no problem. Not sure when the issue began.

When I try now unless the file is very small like 25kb it failed on site 1 with the error

"The server cannot process the image. This can happen if the server is busy or does not have enough resources to complete the task. Uploading a smaller image may help. Suggested maximum size is 2,560 pixels."

However on site 2 the file uploads but the image is distorted with stripes out of alignment. This happens with both Safari and Chrome.

BUT If I use my iPhone through the same wifi -files upload no problem.

Also if I connect my MacBook to my iPhone hotspot which then makes the iPhone switch to 5G - files upload no problem.

I also can't get files on my MacBook to upload on the Fasthosts support site raising a ticket form. It just keeps saying uploading.

Fasthosts have tried at their end and say they can't see any issues with the service and that they can upload files to both WP sites. There has been no change on the WP settings>media form.

I thought it was perhaps because I had been using the beta of Mac OS but I switched that off and nw have a standard version (Took a while to wait for it).

This has me pulling my hair out. I tried clearing out all the caches on Safari but it didn't help. I've restarted laptop and router several times.

Any ideas?