Just replaced cartridge in out single handle turn shower handle and now do not get hot enough water. hat could be the problem?

You likely took out the anti-scald ring out when you took it apart and then put it in in a different spot preventing the handle from turning far enough. You may also have the cartridge or handle upsidedown.

remove and turn cartridge 180 degrees then re-install

change the cartridge

You will need to remove the old cartridge from inside the shower valve body and either refurbish it with new rubber seals and O rings or replace the cartridge altogether (preferable). It's not a complicated fix but the Posi Temp cartridge can be a bear to remove. Moen and Danco make special 'pullers' to make the cartridge removal go a little easier (sold at Lowes/HD and plumbing supply for anywhere between $15 and $35 but well worth it, IMO).

REPLACE THE CARTRIDGE. TURN OFF WATER, REMOVE HANDLE AND FACE PLATE. REMOVE TWO SCREWS UNDER PLATE. PULL OUT CARTRIDGE AND INSERT NEW. REASSEMBLE

You have to remove cartridge and rotate 180 degrees then re-install. Was it removed or replace lately?

change the cartridge it is bad or defective.

take the control apart. and replace the cartirdge. most likely the washer in the cartridge need to be changed.
it is cheaper to get the cartridge then to replace the washer.

make sure when you turn on the hot and cold shut off valves all the way and turn the moen on after that. Some times I would get that problem if I turned one(either hot or cold) off then tried the shower.

it is your shower cartrige. ace hardware $45. hot always goes first. just check if it is a posi-temp or moan trol