HTTPS Custom Icon error

Trying to add a custom icon on an HTTPS site fails:

May 25, 18:40:44 PHP Warning: getimagesize(): Failed to enable crypto in /hidden-path/wp-content/plugins/ultimate-social-media-plus/libs/controllers/sfsi_iconsUpload_contoller.php on line 229
May 25, 18:40:44 PHP Warning: getimagesize(https:/www.ivanov.biz/wp-content/uploads/2016/05/blackduck-1.png): failed to open stream: operation failed in /hidden-path/wp-content/plugins/ultimate-social-media-plus/libs/controllers/sfsi_iconsUpload_contoller.php on line 229
May 25, 18:40:44 PHP Warning: imagecreatefrompng(): SSL operation failed with code 1. OpenSSL Error messages:
error:0D0C50A1:asn1 encoding routines:ASN1_item_verify:unknown message digest algorithm
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed in /hidden-path/wp-content/plugins/ultimate-social-media-plus/libs/controllers/sfsi_iconsUpload_contoller.php on line 243
May 25, 18:40:44 PHP Warning: imagecreatefrompng(): Failed to enable crypto in /hidden-path/wp-content/plugins/ultimate-social-media-plus/libs/controllers/sfsi_iconsUpload_contoller.php on line 243
May 25, 18:40:44 PHP Warning: imagecreatefrompng(https:/www.ivanov.biz/wp-content/uploads/2016/05/blackduck-1.png): failed to open stream: operation failed in /hidden-path/wp-content/plugins/ultimate-social-media-plus/libs/controllers/sfsi_iconsUpload_contoller.php on line 243

https://wordpress.org/plugins/ultimate-social-media-plus/