Parameter Forwarding

Hi,
I want to shorten an affiliate link with the tracking id.
The affiliate link is as follow https://affilaitesite.com/?tid=trackingid

The shorten link https://sho.rt/abcd redirected to https://affilaitesite.com/?tid=

While using Parameter Forwarding,
https://sho.rt/abcd?trackingid must be redirected to https://affilaitesite.com/?tid=trackingid

But the link is redirect to https://affilaitesite.com/?tid=&trackingid,
Character “&” is added in tracking id, Only the alphabets and numbers are accepted as tracking ID.

Is there anyway, the parameter forwarding function works without the “&”?

Thanks.