First off, you are in the wrong forum, this is currently for everything related to the website scirra.com, which does not provide a way to export to Android.
If your issue happens with Construct 3, consider posting in the "How do I" forum for Construct 3.
If it is for Construct 2, consider posting in the "How do I" forum for Construct 2.
The error message you mention means that the project download size you provide or you get is too big.
What is very confusing is what method of export are you using exactly ?
Consider providing all the steps you take to build your application, as well as the tools you use, it will be easier to diagnose your issue and provide help.
Consider following the instructions from the Construct 2 manual (if you are using Construct 2 - The paragraph on "Publishing to mobile" ) or Construct 3 manual (if you are using Construct 3 - Select the appropriate tutorial depending on your target).