.ics file attachment is missing in google mail

Question

i am reading microsoft outlook mail having .ics attachment , converting it into google mail and then writting mail at destination  .

 

i am able to read successfully and verified that i am getting attachment in reading file by saving the same as .eml file on local drive. attachment is coming properly in saved file.

But when i try to write same content on gmail destination .ics attachment is missing. 

 

Note: Only .ics attachment are missing rest of all other are migrating well.