I have a 2.1KW Amerec Sauna timer that will allow heater to heat up, but will only turn off one of the two heating elements. This is a new timer which was installed by a Amerec Service provider but it was not connected correctly I changed the connections so that the elements could receive power but now only one will turn off when the timer is in the off position.

use an electric heater

When I'm in a traditional sauna like this, I expect the temperature to be between 70 and 90C so that's what I assume you are trying to reach. There could be several reasons for this so make sure each point is checked:
1. Stating the obvious, to increase the temperature inside the sauna, you'll have to ladle water onto the hot sauna stones.
2. Maybe the insulation within your sauna isn't good enough and heat is escaping.
3. Your sauna room could be too big for this heater to heat properly.
4. Maybe the element on the heater isn't performing properly and needs to be replaced.

These were some pointers which Di Vapor gave as possible reasons for lack of heat.
Sauna Electric Heaters Spares

I don't know what a sauna has to do with sewing machines... but I suggest that you locate and test the heating element.

Remove the unit bottom panel (2 small screws) and look at the quick disconnect terminals on the heater rods ( 6 heating rods - 3 on each side of the unit). If you have any corrosion on these terminals, the wires will overheat and fail, preventing the heating rods from working. If the wires did overheat, you should see melted wire insulation. Replace bad wire and quick disconnect terminals with new. Should cost less than $20.

Heaters are pretty simple: when timer is on, voltage is applied to the heater elements until timer turns off. To troubleshoot your problem, use a multimeter or circuit tester to check the terminal connections on the heating elements themselves. With the timer ON, you should be able to read voltage (120 or 240, depending on your heater) at those connections. If you don't check the continuity of the wiring from your timer to your heater. Continuity w/out voltage at the element indicates a faulty timer, no continuity means bad wiring. If you do read voltage at the element but it isn't heating, your element is burnt out -- time to replace it. If it's a newly assembled setup or seems odd to be burnt out for some other reason, double check that you're using the correct voltage for that particular heater... 120vac won't run a heater rated at 240vac.

more than likley installation problem not enough voltage top operate heating element

the 'easy' answer would be a tripped high-limit switch. Inside the generator box, there is a resettable circuit breaker to the heating element, on the top of the water tank.
kill the power to the unit, take off the shell and look for the pushbutton.
If that is the problem, there is a likely chance that the temp sensor in the shower is not working so it overheats and trips the high temp limit.