Welcome to the community forum . Thanks for posting here.
I assume that you deployed a logic contract and proxy manually on Remix rather than using the OpenZeppelin CLI? I also assume that you didn’t deploy a ProxyAdmin contract to be the admin of the proxy.
Would you mind sharing some details on how you deployed the contracts?
As for how to interact with your contract:
If the caller is the admin of the proxy (the address with rights to upgrade the proxy), then the proxy will not delegate any calls, and only answer any messages it understands.
If the caller is any other address, the proxy will always delegate a call, no matter if it matches one of the proxy’s functions.
See the documentation for details:
This means if you want to interact with your contract, you need to call the functions using the address of the proxy from an account that isn’t the admin of the proxy. So you would need to change accounts in Remix/MetaMask.