I have been using D&D beyond for a while now, but at the moment it is frustrating me. When I go into Collections>My Characters A loading wheel pops up, and it says I have created zero characters. However, when I go into My Campaigns they show up there, but when I try to access them I am met with this Error screen with a picture of a zombie beholder.

Whoops! We rolled a 1 on our API check. We're heading into town to visit the blacksmith for repairs.

Try again after a Short Rest.

Are you running and ad/popup blockers, browser extensions, or a VPN that may be interfering with DDB?

i have been running an adblocker for a while, but it does not appear to affect the situation when I turn it off

Is that the only one?

What Browser are you using?

Did you have a subscription that recently changed?

I have kinda the same problem. 

Been using Chrome + uBlock for longer than DDB and it worked all the time. Just in the last few days i got the 500Error and it seems to take forever to open "Manage Equipment" in the Sheets of different characters (mine and from others in my campains)

edit: Been using DDB for some years now with Chrome+uBlock

If either Chrome, uBlock, or DDB had a recent update it is possible that some things stopped cooperating with each other. For example, you may need to update your uBlock, or uBlock may need to issue an update.

Chrome and its extensions are fairly notorious around here for those kinds of glitches.

Chrome GX without any plugins / addons has the same problem. Just checked. 
Also, no further updates available for chrome/ublock. using chrome without ublock didn't help either. 

To be clear, i'm just talking about the very slow equipment management part (atm i can see and access all my characters)

ok, im on a school chromebook, might that have any effect?

Quote from Leodan >>

ok, im on a school chromebook, might that have any effect?

 Maybe. Since it’s a school machine there may be a VPN or something that has this site (or one of the other sites it needs to run properly) blacklisted.

Maybe. It might also have something to do with this: I was looking at the screen and was trying to figure out the issue and noticed that in the corner it said "My Characters Version: v0.0.23"

is that what it is supposed to say? is there anything I can do to fix it?

Try logging out and back in, then give it about 20 minutes and check it again.