I see the signal at x3 the desired frequency. (Aliasing?)

Dear All,
My signal of Interest is around 70 MHz @ -50 dBm. When I inject a signal around 210 MHz @ -50 dbm the signal at 210 MHz becomes prevalent. Is there a mixer setting to prevent aliasing?
Thanks in advance.

The simplest option is to add an external LPF Low Pass Filter (or Band Pass Filter) with a cutoff at a frequency anywhere above 70 MHz.
Either buy one or build one
e.g.

Or see other suggestions in the linked thread, the last post in that thread has some really good information.