(gdb) bt                                                                                                                                                                                                                                     
#0  0x00007fe330b8a0a0 in zend_fetch_resource () from /usr/lib/apache2/modules/libphp7.2.so                                                                                                                                                  
#1  0x00007fe328c666b9 in ?? () from /usr/lib/php/20170718/mapi.so                                                                                                                                                                           
#2  0x00007fe31d5685e4 in ?? () from /usr/lib/x86_64-linux-gnu/kopano/libkcclient.so                                                                                                                                                         
#3  0x00007fe31d56b5a0 in ?? () from /usr/lib/x86_64-linux-gnu/kopano/libkcclient.so                                                                                                                                                         
#4  0x00007fe328c8bfa2 in ?? () from /usr/lib/php/20170718/mapi.so                                                                                                                                                                           
#5  0x00007fe330c2407b in execute_ex () from /usr/lib/apache2/modules/libphp7.2.so                                                                                                                                                           
#6  0x00007fe330b63fee in zend_call_function () from /usr/lib/apache2/modules/libphp7.2.so                                                                                                                                                   
#7  0x00007fe330a9b504 in ?? () from /usr/lib/apache2/modules/libphp7.2.so                                                                                                                                                                   
#8  0x00007fe330c2407b in execute_ex () from /usr/lib/apache2/modules/libphp7.2.so                                                                                                                                                           
#9  0x00007fe330b63fee in zend_call_function () from /usr/lib/apache2/modules/libphp7.2.so                                                                                                                                                   
#10 0x00007fe330a9b504 in ?? () from /usr/lib/apache2/modules/libphp7.2.so                                                                                                                                                                   
#11 0x00007fe330c2407b in execute_ex () from /usr/lib/apache2/modules/libphp7.2.so                                                                                                                                                           
#12 0x00007fe330c259b7 in zend_execute () from /usr/lib/apache2/modules/libphp7.2.so                                                                                                                                                         
#13 0x00007fe330b745a2 in zend_execute_scripts () from /usr/lib/apache2/modules/libphp7.2.so                                                                                                                                                 
#14 0x00007fe330b10490 in php_execute_script () from /usr/lib/apache2/modules/libphp7.2.so                                                                                                                                                   
#15 0x00007fe330c27b12 in ?? () from /usr/lib/apache2/modules/libphp7.2.so                                                                                                                                                                   
b#16 0x00005615d7db0be0 in ap_run_handler ()                                                                                                                                                                                                 
#17 0x00005615d7db115d in ap_invoke_handler ()                                                                                                                                                                                               
#18 0x00005615d7dc80ec in ap_internal_redirect ()                                                                                                                                                                                            
#19 0x00007fe32c8f3f35 in ?? () from /usr/lib/apache2/modules/mod_rewrite.so                                                                                                                                                                 
#20 0x00005615d7db0be0 in ap_run_handler ()                                                                                                                                                                                                  
#21 0x00005615d7db115d in ap_invoke_handler ()                                                                                                                                                                                               
#22 0x00005615d7dc8d1b in ap_process_async_request ()                                                                                                                                                                                        
#23 0x00005615d7dc8ef0 in ap_process_request ()                                                                                                                                                                                              
#24 0x00005615d7dc513d in ?? ()                                                                                                                                                                                                              
#25 0x00005615d7dba9f0 in ap_run_process_connection ()                                                                                                                                                                                       
#26 0x00007fe331192831 in ?? () from /usr/lib/apache2/modules/mod_mpm_prefork.so                                                                                                                                                             
#27 0x00007fe331192b44 in ?? () from /usr/lib/apache2/modules/mod_mpm_prefork.so                                                                                                                                                             
#28 0x00007fe3311935b4 in ?? () from /usr/lib/apache2/modules/mod_mpm_prefork.so                                                                                                                                                             
#29 0x00005615d7d9419e in ap_run_mpm ()                                                                                                                                                                                                      
#30 0x00005615d7d8ca7b in main ()