Hi @shubham I also had the same problem. There is already a thread on the forum about this here: Problem in Snaphu Import section but I think you are using the wrong file for the Read-Phase.
For the Read-Phase you should use the phase that you used in the SNAPHU exporting (the input data in .dim format). For me this file was called S1A…Orb_Stack_ifg_deb_dinsar_flt.dim. If I use the Phase_ifg_srd_…snaphu.hdr file I get the same error as you. Does that help?