Not sure if it's just a temporary glitch but it sounds like you transferred too many items between your accounts, or made some suspicious exchanges lately. Best write to support and submit screenshots of the error in question.

nah, having the same problem for months now. Can only access my inventory rarely if I'm lucky. I can't even use it properly, so I obviously don't make many inventory-requests.
Only workaround I'm aware of is using a VPN or some other IP connection to access your inventory. No other workaround I'm aware of.

I have the same problem, and i rarely even do trades or sell items. i want to sell some items now cuz of the autumn sale, but its been weeks that i cant access market

It's an IP rate limit.

same here

I just looked at a few skins and sold an item now I can't acces the market nor my inventory for hours

is this a joke valve?

Same here. I even tried diifferent IP nothing helps.

Yeah I tried it with different IP from my phone and LTE connection but problem persists.

Good god. How bad Steam is nowadays with all these restrictions.

Has it occurred to any of you that you're being throttled, and that maybe even your accounts are flagged by Valve? The thing is if they shut down market manipulators. Ninety percent of problems will go away along with them.