You have tried to submit your FPS or EPS and are getting this error back from HMRC. This error could mean that HMRC are not expecting you to file your RTI. There could be a few reasons for this:
You have ceased your PAYE scheme and HMRC have closed your account.
You have not filed a RTI for the PAYE scheme and so HMRC have closed your account.
You asked HMRC to set your PAYE scheme from a certain date and you are trying to file an RTI before the date the PAYE scheme was made active.
In all the above cases you will need to contact HMRC.
You will need to contact HMRC and tell them you are receiving the error message "This submission cannot be accepted as it does not fall within the eligible filing period" (error number 7806). Only HMRC can tell you why they are not expecting RTI returns for your PAYE scheme. We cannot solve this issue for you.