Battlefield 4: You need a solider to join this server

Try this...  

open Origin, double click on the BF4 icon so Origin opens and logs you into Battlelog with your Origin account and that will create your soldier on the spot and allow you to play.

Thanks for your help but your solution didn't fix the problem

Also there's no option there to let me access Campaign mode
It just shows a YouTube video with the BF4 campaign trailer...

For Campaign mode open origin then right click on BF4 and pick play .. this will open battlelog ....at the very top of battlelog you will see solder, multiplayer , campaign ,platoons and leaderboards. Pick campaign if this fails for you.... then try repair game or uninstall all traces of BF4 from the PC but also remove the BF4 folder in my documents before you reboot PC. Then reboot PC  and then do a clean install of BF4. If all this fails then I would contact a EA game adviser to fix this.

Follow the Steps to contacting an EA Game Adviser to fix this :

1 Click here to go to the EA contact page. http://help.ea.com/en/

Note: Top left pick your Country :]

2 Select your game and platform, Then click next.
3 Select a topic and write about your problem.
4 Click next and select your preferred contact method.
5 Ask for a callback if you can as it is fast when I used it.

Or use this

You can contact EA here: http://help.ea.com/en/contact-us/

http://help.ea.com/ca/article/welcome-to-the-new-and-improved-ea-help-center/#contact

The call back feature available to North America, Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Hungary, Ireland, Italy, Netherlands, Norway, Poland, Portugal, Russia, Spain, Sweden, Slovakia, Switzerland, and the UK.