UPDATE:

Procurement 1.9.8-RC1 has been released:

https://github.com/Stickymaddness/Procurement/releases/tag/1.9.8-RC1

Please retest with this version, if you are using sessionID first log out of the forum, clear your cookies and then log back in using the POESESSID cookie to get your sessionID.

Expecting state 'Element' error

This highly annoying issue appeared shortly after the PoE 2.1 content update. The problem with this error is that it is incredibly difficult to resolve as in most cases the issue is on GGG's side and there is no quick solution that works for everyone.

From a technical point of view, the error is that the GGG API is returning "false" when Procurement makes a request for stash data and as such cannot continue loading. GGG recently changed some of the API urls as well as the responses. My theory is that the error is a result of the server seeing the user as not authenticated when in fact they are, and returning "false" instead of the item json.

Below is an attempt to document the different solutions that helped other users that received this error. If you find a solution that is not documented below, please let me know.

Covering the basics on your end

Make sure that you have tried:

1. Running as administrator
2. Logging in with SessionID (still requires account name)
3. Checked that no AV or firewall software is interfering with Procurement's connection

Your account name is wrong

Due to the unfortunate addition of account name to the GGG API, Procurement will return an error shortly after login if your account name is incorrect. Note that:

1. Account name is case sensitive
2. It is required even if you login using sessionID
3. Account name is the name that you post under on the forums

Login to the forum with a different browser

In some cases logging out of the forum and back in again, or logging into the forum with a different browser, and then using the sessionID from the new browser to login to Procurement has fixed this issue.

Test your stash on the forum

If nothing has worked so far, login to the forum and try view your characters and stash. If your items are not loading, contact GGG support and tell them that your character inventories/stash is not loading on the forum. When they fix it, most likely you will be able to login to Procurement.

Wait and try again

As ridiculous as it sounds, for a number of users the issue suddenly goes away and they are able to login to Procurement. I attribute this to the fact that the fault lies on GGG's side.

Beyond this there is nothing I can do to assist, I have contacted GGG and will keep this updated.