Help needed: Can’t withdraw contribution??

I’m trying to withdraw a contribution because I dropped the pin in the wrong spot. I click the ‘withdraw’ button, sometimes I get an error message (error 5) and sometimes just nothing happens. My only option is to ‘cancel’. What am I doing wrong?
Thanks so much for any help anyone can offer!
Comments
If your nomination is already in voting, it can't be withdrawn.
Once it's in voting it can't be edited or withdrawn.
It’s not in voting. Still in queue.
Has it been upgraded?
You didn't say if you marked it to Upgrade or Upgrade Next, so I didn't think about that. I don't believe you can withdraw if you hit either of those buttons. Would help if you had shown a screenshot. See my other reply here:
https://community.wayfarer.nianticlabs.com/discussion/comment/176209/#Comment_176209