When I use actual values on `curl` command in the next script, it's working and giving me a result back, but when I use variables it does not work properly 

I think this is issue with how I define them on the command

```
amz_t=$(cat amazon-token.txt )
flx_id=$(cat flex-id.txt )
ses_t=$(cat session-token.txt )

curl -s -H 'Host: flex-capacity-na.amazon.com' \
  -H 'Cookie: session-token='$ses_t'' \
  -H 'x-amz-access-token: '$amz_t'' \
  -H 'x-flex-instance-id: '$flx_id'' \
  -H 'Accept: */*' \
  -H 'User-Agent: iOS/10.2.2 (iPhone Darwin) Model/iPhone Platform/iPhone6,1 RabbitiOS/2.0.141' \
  -H 'Accept-Language: en-us' \
  --compressed 'https://flex-capacity-na.amazon.com/GetOffersForProvider?serviceAreaIds=122' >> output.txt

```

This is the command I try to run in script above mention txt files only contain the certain values no garbage values.