This most likely happens because mods are made for specific versions of games. When games get updated, some or all mods will stop working requiring us to update mods. You have a few options
You can get the same game version as the version Mod Engine works for. Sometimes it is possible to downgrade game versions, other times it is not.
You can request updates to the mods.
We are a small team with thousands of games supported in Mod Engine. Please be patient while we get through update requests, we can’t give an ETA to when we will get to your mod update request.
Please note that PRO members are given priority and their update requests are fulfilled asap.