External users unable to download Lync GAL

Hello Expert,

i have issues with Lync Gal, my external users unable to download the GAL.  when i ran the Lync configuration from lync client, i got to know GAL url is taking my internal website URL "pool1.domain.local).. i am not sure why it is taking internal web URL and this internal url is not rechable outside or internet due to pool1.domain.local. i am not sure how to change this GAL URL to external website URL. i hope this will resolve my problem. any help regards to this greatly appricated.

here is my lync configuration output for your reference.

DG URL Internal;https://pool1.hosting.local:443/groupexpansion/service.svc;--;
DG URL External;https://lyncweb.exchangemails.com:443/groupexpansion/service.svc;--;
Quality Metrics URI;sip:pool1.hosting.local@hosting.local;gruu;opaque=srvr:HomeServer:0AE5zW36FFihpJf8TdUKzgAA;--;
URL Internal From Server;https://pool1.hosting.local:443/abs/handler;--;
URL External From Server;https://lyncweb.exchangemails.com:443/abs/handler;--;
Voice mail URI;sip:manoj.bojewar@globaloutlook.com;opaque=app:voicemail;--;
Exum Enabled;FALSE;--;
Exum URL;;--;
MRAS Server;sip:goh-lyncedge.hosting.local@hosting.local;gruu;opaque=srvr:MRAS:UdeU1d6lTlWoqVSEUh0e4AAA;Enabled;
GAL Status;https://pool1.hosting.local:443/abs/handler;Cannot synchronize with the corporate address book. This may be because the proxy server setting in your web browser does not allow access to the address book. If the problem continues, please contact your support team.;
Controlled Phones;TRUE;--;
PC to PC AV Encryption;AV Encryption Supported;--;
Focus Factory;sip:manoj.bojewar@globaloutlook.com;gruu;opaque=app:conf:focusfactory;--;
Telephony Mode;Telephony Mode Disabled;--;
Line;;--;
Line Configured From;Auto Line Configuration;--;
Location Profile;DefaultProfile;--;
Call Park Server URI;;--;
UCS Mode;Lync Server Mode;--;
Configuration Mode;Auto Configuration;--;
Server Address Internal;--;--;
Server Address External;--;--;
Server SIP URI;manoj.bojewar@globaloutlook.com;--;
GAL or Server Based Search;GAL search;--;
Local Log Folder;C:\Users\Manoj\tracing;--;
MAPI Information;MAPI Status OK;MAPI Status OK;
EWS Information;--;EWS Status OK;
Inside User Status;FALSE;--;
Auto Update Download Started;--;--;
Auto Update Download Completed;--;--;
Last Auto Update Request;--;--;
Pairing State;Lync cannot connect to your desk phone because the USB cable is not plugged in. Make sure that you connect the cable.;Enabled;
Contact List Provider;Lync Server;--;
UCS Connectivity State;Exchange connection Down;--;
Connected Lync Server;sip.exchangemails.com;--;
Skill Search URL;;--;
SharePoint Search Center URL;;--;
EWS Internal URL;https://goh-cas02.hosting.local/EWS/Exchange.asmx;--;
EWS External URL;https://webmail.exchangemails.com/ews/exchange.asmx;--;