Unable to add new language or pot file (buttons not clickable)

Hi. When having selected a plugin to translate in Loco 2.6.9, I click “new language”, then selecting a language and file location. Whatever I choose, the “Start translating” button is greyed out and not clickable.

On top of the page, there is a “Notice:” message, which is empty. Happens in loco for all plugins. Also when I try to upload a po-file, the Upload button is not clickable.

Logged in as site admin

Versions
Loco Translate:
2.6.9
WordPress:
6.5.3
PHP:
7.4.33 (apache2handler)
Server:
Apache/2.4 + mod_so, mod_mime, mod_log_config, mod_logio, mod_expires, mod_headers, mod_setenvif, mod_version, mod_remoteip, mod_unixd, mod_vhost_alias, mod_dir, mod_alias, mod_rewrite, mod_access_compat, mod_allowmethods, mod_auth_basic, mod_auth_digest, mod_authn_anon, mod_authn_core, mod_authn_dbd, mod_authn_dbm, mod_authn_file, mod_authz_core, mod_authz_dbm, mod_authz_groupfile, mod_authz_host, mod_authz_user, mod_data, mod_env, mod_filter, mod_mime_magic, mod_negotiation, mod_reqtimeout, mod_slotmem_plain, mod_slotmem_shm, mod_status, mod_substitute, mod_systemd, mod_lua, mod_php7
jQuery:
...
Zend OPcache:
7.4.33
Unicode
UTF-8 rendering:
ΟΚ ?
Multibyte support:
ΟΚ ?
Site character set
UTF-8 ?
Ajax
Endpoint:
/wp-admin/admin-ajax.php
JSON decoding:
ΟΚ ?
Translation APIs
DeepL Translator:
Google Translate:
Lecto AI:
Microsoft Translator:
Limits
WP_MEMORY_LIMIT:
256 MB
WP_MAX_MEMORY_LIMIT:
256 MB
PHP memory_limit:
256 MB
PHP post_max_size:
50 MB
PHP max_execution_time:
120
Filesystem
File mods disallowed:
No
File mod safety level:
Warn
LOCO_LANG_DIR:
wp-content/languages/loco ?
PHP sys_temp_dir:
/tmp ?
PHP upload_tmp_dir:
/tmp ?
PHP error_log:
(none) 
PHP open_basedir:
Debug settings
WP_DEBUG:
Off
WP_DEBUG_LOG:
Off
WP_DEBUG_DISPLAY:
On
PHP display_errors:
Off
PHP log_errors:
On