Lots of variables, I just happened to see this post but I thought I could at least help you get started troubleshooting.

What device are you using? Do you get the same error if you're on a different device(Android/iOS vs desktop/laptop)

What browser or app are you using(Safari, Chrome, Firefox, Jerboa, Mlem?) If you can use a browser and open dev tools(F12) and take note of what happens(warnings/errors POST requests) when clicking on the upvote button may help the devs of the app(if you're using one) or instance maintainer figure out what's going on

Have you checked to see if the post you're trying to upvote is within your instance vs a federated post?

I'll reply if I can later, just thought I'd ask these questions to get you started. May want to check > out !/c/techsupport and/or !/c/lemmy_support to see if there are people having similar issues.

Musk's gon' bill it to ya

Tired of tweeting for free? X's gonna monetize ya

Tap tap, open up the app, it's free...

With the non-stop, cash grab of premium fees

Riding rockets, now he's starbound and sold

But he got such a grand scheme

That'll make a tweeter wonder if he’s been memed

Damn right, and he'll charge you again, 'cause he's Elon, so hes gots to win

Tweet battles with the freemium, but no matter how many cats he boxes with, he'll profit on your scene and win

^

For those that don't know, you can only disable the footer signature on the desktop or mobile web client(in desktop mode). It's kinda of tucked away but once you login, at the top right there's a settings menu at the top right(with a cog icon) -> open the drop-down -> settings ->

Worth checking out:

https://github.com/andrewbanchich/shreddit

It also has the ability to wipe your GDPR data for those in the EU.

As @JapanStar49 said, mass edit, don't mass delete. IMO this is just as good as a greasemonkey script at mass editing your history to remove your reddit paper trail.