You can go into Windows device manager and look for any device showing issue.
Normally with an exclamation mark against it.
Sometimes it is as easy as right clicking on the problem device and choose “update driver” and then select an MTP driver (already on your PC and you should see a list of options when you click on “choose from available drivers”) and test it.
In the days of Android 5.1 this usually works.
If not, then you can install the MTK driver package.