Cannot connect to VPN at home office from specific location

I can connect to my home office from several locations, but recently a customer reported that they could not connect to my network.  I obtained the following tracert from them, which seems to indicate they are not reaching my network.

More information:

I regularly connect to my office from external networks.  Users in different states can connect to this network via VPN.  User is behind a firewall managed by the government agency they work for.  Tracert seems to get ourside that firewall, but route halts short of reaching my network (see tracert).

Tracing route to 75-144-45-97-Atlanta.hfc.comcastbusiness.net [75.144.45.xx]
over a maximum of 30 hops:

  1    <1 ms    <1 ms    <1 ms  1960-mdf-211-6509.sarasota.k12.fl.us [10.1.104.1]
  2    <1 ms    <1 ms    <1 ms  landings-inet6509.sarasota.k12.fl.us [10.194.0.1]
  3     1 ms     1 ms     1 ms  172.22.1.26
  4     2 ms     2 ms     1 ms  10.198.1.4
  5     2 ms     2 ms     2 ms  204.193.7.1
  6     3 ms     2 ms     2 ms  74.120.47.205
  7     4 ms     4 ms     4 ms  m1049-tape-10ge-10-1-4.fplfn.net [208.67.164.190]
  8     9 ms     9 ms     9 ms  m1049-mts-10ge-10-2-2.fplfn.net [208.67.166.129]
  9     9 ms     9 ms     9 ms  m1070-nap-10ge-2-0-0.fplfn.net [208.67.166.66]
 10    11 ms    11 ms    11 ms  be-10-902-pe01.nota.fl.ibone.comcast.net [66.208.228.113]
 11    13 ms    11 ms    11 ms  pos-1-3-0-0-cr01.miami.fl.ibone.comcast.net [68.86.87.229]
 12    19 ms    18 ms    20 ms  he-0-11-0-0-cr01.56marietta.ga.ibone.comcast.net [68.86.88.213]
 13    26 ms    29 ms    19 ms  68.86.94.42
 14    19 ms    19 ms    19 ms  xe-0-1-0-0-sur01.b5mableton.ga.atlanta.comcast.net [68.85.108.186]
 15    30 ms    39 ms    30 ms  te-17-10-cdn01.b5mableton.ga.atlanta.comcast.net [68.86.109.130]
 16    28 ms    29 ms    28 ms  c-24-126-143-161.hsd1.ga.comcast.net [24.126.143.161]
 17     *        *        *     Request timed out.
 18     *        *        *     Request timed out.
 19     *        *        *     Request timed out.
 20     *        *        *     Request timed out.
 21     *        *        *     Request timed out.
 22     *        *        *     Request timed out.
 23     *        *        *     Request timed out.
 24     *        *        *     Request timed out.
 25     *        *        *     Request timed out.

What could be the issue and the solution?

Thanks in advance.