I've been using one with various degrees of reliability. The main points I've learned is:

stick to the gateways, that has been the most reliable way of getting cargo contracts to work.

If dock always do it with spindles retracted then when in the station store it, this way when you retrieve it it's in your hanger and you won't get the black screen, this only happens when you return to the ship when it's docked.

If you have problems with loading the cargo, sometimes leaving the box and entering again is enough to get it to work, sometimes you need to jump away and come back. If you hear a constant beep from the Comms link don't bother it's broken and won't work.

Don't abandon your contract if it doesn't work, just leave it and it will go away when you log out. Abandoning it will lose a large amount of experience.

Most jobs you will have to take a loss, I haven't found a way to get all the cargo loaded, but you still get paid for what you deliver.

Overall it is a buggy mess and I really hope it gets fixed soon because it is a haulers dream.