you need to export the po and mo files from here https://translate.ww.wp.xz.cn/projects/wp-plugins/ultimate-member/dev/es/default
and then rename ultimate-member-es_ES.po and ultimate-member-es_ES.mo and upload in /wp-content/languages/plugins/
@aghorbanmehr Thank for the tip “changed ultimatemember to ultimate-member”. This simple change worked for my translation in Spanish! I was going crazy
