It depends. Are you newly formed and this is your first year of filing? If so, It's 1120-H fed, and 1120ME Maine. If not, and the cycle of filing was broke, it's 1120 fed. Maine is  the same form(1120ME)

You will then be subject to back taxes if any along with a penalty and interest charges. Once your current you can then file an 1120H for fed. and 1120ME for Maine for succeeding years.

I highly recommend you hire a CPA and keep him for tax preparation yearly. An outside professional source for taxes maintains less chance for future complicated and costly challenges that are at high risk of happening from succeeding treasurer's who are not properly informed of the process, and certainly most likely not familiar with corporate tax prep. Doing personal taxes is hard enough.

The 1120-H is designed for the case you state. The 1120 which was required before the H came along not so much.

My experience involved a road association that hadn't filed a return for over several years. Needless to say after working with the IRS, MSR, and guided by a CPA the 1120 had to be used to become current. Back taxes were due under that filing, penalties forgiven(after a lawyer's letter was submitted explaining why returns were not submitted for those years), but interest charged. It was expensive.

Now being current and using the 1120-H taxes are not due but if the cycle is broken you must file the 1120 with possible risk as stated.