There was an error submitting the form while creating DP channel

My first time using DP or ROKU andI can't seem to be able to upload branding images, anytime I upload and click save, it returns "There was an error submitting the form while creating" message. It's quite a frustrating experience as the error message does not give any description on what to do next or possible causes.

The image size/resolution are good, so it's not from there.

Please any help on how to go around this? Would be very grateful for any hints or perhaps how long this might take to fix.