You cannot attach files with restricted extensions and same names to a template.
The following extensions are restricted:
0xe, 73k, 89k, 8ck, a6p, a7r, ac, acc, acr, actc, action, actm, ade, adp, ahk, air, apk, app, applescript, arscript, asb, asp, aspx, azw2, ba_, bas, bat, beam, bin, btm, caction, cel, celx, cer, cgi, chm, cmd, cnt, cof, coffee, com, command, cpl, crt, csh, cyw, dek, der, dld, dmc, dmg, ds, dxl, e_e, ear, ebm, ebs, ebs2, ecf, eham, elf, epk, es, esh, ex4, ex5, ex_, exe, exe1, exopc, ezs, ezt, fas, fky, fpi, frs, fxp, gadget, gpe, gpu, grp, gs, ham, hlp, hms, hpf, hpj, hta, html, icd, iim, inf, ins, ipa, ipf, isp, isu, ita, its, jar, js, jse, jsf, jsx, kix, ksh, kx, lnk, lo, ls, m3g, mac, mad, maf, mag, mam, maq, mar, mas, mat, mau, mav, maw, mcf, mcr, mda, mdb, mde, mdt, mdw, mdz, mel, mem, mio, mlx, mm, mpx, mrc, mrp, ms, msc, msh, msh1, msh2, mshxml, msh1xml, msh2xml, msl, msi, msp, mst, mxe, n, ncl, nexe, ops, ore, osd, osx, otm, out, paf, paf.exe, pcd, pex, php, phar, pif, pkg, pl, plg, plsc, plx, prf, prc, prg, ps1, ps1xml, ps2, ps2xml, psc1, psc2, pst, pvd, pwc, pyc, pyo, qit, qpx, rbf, rbx, reg, rfu, rgs, rox, rpj, run, rxe, s2a, sbs, sca, scar, scb, scf, scpt, scptd, scr, script, sct, seed, server, sh, shb, shs, spr, smm, svg, tcp, thm, tiapp, tmp, tms, u3p, udf, upx, url, vb, vbe, vbp, vbs, vbscript, vdo, vexe, vlx, vpm, vsmacros, vsw, vxp, wcm, widget, wiz, workflow, wpk, wpm, ws, wsc, wsf, wsh, x86, xap, xbap, xlm, xml, xnk, xqt, xys, zl9
