facebook developer site indicates that the image might be bigger than 8Mb, but all our images are just som kB big, or server being slow, but this is not the case, as this issue has been going on for some 3 days now.
PHP on server is V 7
WordPress is V 4.7.3–es_ES
Parabola is V 2.1.3
All In One SEO Pack is V 126.96.36.199