I have been doing the tax returns for my grandchildren. I have filed 5 returns and it won't let me file the last 2(including mine). What do I do/

If you have already E-filed 5 returns, that is the limit of the Desktop software.  

• You can file the last two by Mail.
• The limit is an IRS limit that means
  • One user cannot e-file more than five federal returns in ONE specific tax year. 

5 is an IRS limit.  You will have to print and mail the rest.  Next year efile yours and the more complicated returns first and mail the simple ones.  Maybe some returns can use the Online Free Edition?  Or the IRS Free File

https://www.irs.gov/filing/free-file-do-your-federal-taxes-for-free 

Mail the last two returns.  The five federal e-file limit is an IRS limit.

When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s.  Use a mailing service that will track it, such as certified mail so you will know the IRS/state received the return.

Federal and state returns must be in separate envelopes and they are mailed to different addresses.  Read the mailing instructions that print with your tax return carefully so you mail them to the right addresses.