[horde] Issue contacting server after upgrade

[poubeline at free.fr]

Hi All, 

I have horde groupware webmail edition 5.2.22 running on debian server 9.4. 
All was running fine and I checked on the administration side that there was some updates available for some components of Horde. 
So I did some upgrades like this : 
pear install --alldeps channel://pear.horde.org/horde_activesync-2.39.3 

Updates I did are : 
horde_cli-2.3.0 
horde_activesync-2.39.3 
horde_core-2.31.3 
horde_crypt-2.7.12 
horde_cssminify-1.0.4 

Everything when fine but when I click on the 'Check for new versions' button, I get the error 'Cannot connect to server. Try later'. 
I have checked the syslog file for Horde and the only thing relevant I have is a memory usage limit for registry.php. 

Looking at some solutions about it on the web just points that it is a warning message but not a failure and that I can forget about it. Thought it is true as the memory displayed for this warning is far below my php.ini setting. 

Can someone help me point out why I cannot connect to the server for checking new versions ? 
Is that something that has to do with the pear channel configuration ? When I type 'pear channel-update pear.php.net' it displays 'Channel "pear.php.net" is up to date'. 

Thanks for your help. 

Laurent